WO2025034848A1

WO2025034848A1 - Methods, architectures, apparatuses and systems for anchor device selection for bistatic sensing

Info

Publication number: WO2025034848A1
Application number: PCT/US2024/041275
Authority: WO
Inventors: Remun KOIRALA; Fumihiro Hasegawa; Paul Marinier; Tao Deng; Ognen OGNENOSKI; Tuong Hoang; Moon Il Lee; Kunjan SHAH; Janet Stern-Berkowitz
Original assignee: InterDigital Patent Holdings Inc
Current assignee: InterDigital Patent Holdings Inc
Priority date: 2023-08-07
Filing date: 2024-08-07
Publication date: 2025-02-13
Anticipated expiration: 2026-02-07

Abstract

Procedures, methods, architectures, apparatuses, systems, devices, and computer program products for bistatic sensing. In certain representative embodiments, a wireless transmit/receive unit (WTRU) may receive information indicating reference signal (RS) configurations; first and second time thresholds; and transmission/reception point (TRP) locations. The WTRU may select a first set of TRPs. The WTRU may send an uplink bistatic sensing request including information indicating the first set, the obstacle location, and/or the WTRU location. The WTRU may receive an uplink bistatic sensing acknowledgment including information indicating a second set of TRPs. The WTRU may select one or more of the RS configurations based on the first and second time thresholds, and TRP locations of the second set. The WTRU may transmit one or more RSs using the one or more RSs configurations. The second set of TRPs may receive the transmitted RSs and perform bistatic sensing of the obstacle.

Description

METHODS, ARCHITECTURES, APPARATUSES AND SYSTEMS FOR ANCHOR DEVICE SELECTION FOR BISTATIC SENSING

CROSS-REFERENCE TO RELATED APPLICATIONS

[OOO1] This application claims the benefit of U.S. Provisional Patent Application No. (i) 63/531 ,096 filed 07-Aug-2023, which is incorporated herein by reference.

TECHNICAL FIELD

[0002] The present disclosure is generally directed to the fields of communications, software and encoding, including, for example, to methods, architectures, apparatuses, systems directed to bistatic sensing.

BACKGROUND

[0003] 5G NR Sensing involves detecting, estimating, and monitoring conditions of the environment and/or objects within the environment (e.g., shape, size, orientation, speed, location, distances or relative motion between objects) using NR RF signals. The presence of obstacles may pose safety problems to users and/or devices in the vicinity thereof. Solutions which improve and/or enhance sensing are desirable.

SUMMARY

[0004] In a representative embodiment, a wireless transmit/receive unit (WTRU) may receive information indicating (i) a plurality of sounding reference signal for positioning (SRSp) configurations, (ii) a first time threshold and a second time threshold which are associated with the plurality of SRSp configurations, and (iii) assistance information indicating a plurality of transmission/reception point (TRP) locations of a plurality of TRPs. The WTRU may detect an (e.g., coarse) obstacle location of an obstacle. The WTRU may select a first set of the TRPs from the plurality of TRPs. For example, the first set of TRPs may be WTRU-preferred TRPs for bistatic sensing. For example, each TRP of the first set may be associated with a RTT, between the obstacle location and the TRP location of the respective TRP, which is above the first time threshold and below the second time threshold (e.g., a RTT that satisfies a sensing coverage area). The WTRU may send, to a network, an uplink bistatic sensing request which includes information indicating any of (i) the first set, (ii) the obstacle location, and/or (iii) a WTRU location of the WTRU. The WTRU may receive, from the network, an uplink bistatic sensing acknowledgment which includes information indicating a second set of the TRPs. For example, the second set of TRPs may be selected by the network, such as based on the first set of TRPs indicated by the WTRU. The WTRU may select one or more SRSp configurations from the plurality of SRSp configurations based on the first time threshold, the second time threshold, and the TRP locations of the second set of the TRPs. The WTRU may transmit one or more SRSps using one or more SRSp resources of the selected one or more SRSp configurations. For example, the second set of TRPs may receive the transmitted SRSps and perform bistatic sensing of the obstacle. [0005] In a representative embodiment, a network entity may send, to a WTRU, information indicating (i) a plurality of SRSp configurations, (ii) a first time threshold and a second time threshold which are associated with the plurality of SRSp configurations, and (iii) assistance information indicating a plurality of TRP locations of a plurality of TRPs. The network entity may receive, from the WTRU, an uplink bistatic sensing request which includes information indicating any of (i) a first WTRU-preferred set of the TRPs from the plurality of TRPs, (ii) a first (e.g., coarse) obstacle location of an obstacle, and/or (iii) a WTRU location of the WTRU. For example, each TRP of the first set may be associated with a RTT, between the obstacle location and the TRP location of the respective TRP, which is above the first time threshold and below the second time threshold. The network entity may send, to the WTRU, an uplink bistatic sensing acknowledgment which includes information indicating a second network-selected set of the TRPs. For example, the second set of TRPs may be selected by the network, such as based on the first set of TRPs indicated by the WTRU. The network entity may send, to the WTRU, information indicating a second (e.g., fine) obstacle location of the obstacle. For example, the second obstacle location may be (e.g., determined) based on reception of one or more SRSps using one or more SRSp resources of one or more of the plurality of SRSp configurations by the second network-selected set of the TRPs.

[0006] In a representative embodiment, a WTRU may receive information indicating a set of reference signal (RS) configurations (e.g., PRS, SRSp, CSI-RS, DM-RS, SSB, and/or etc.). The WTRU may send an uplink bistatic sensing request which includes information indicating a first set of (e.g., preferred) TRPs, an obstacle location of an obstacle, and a WTRU location of the WTRU. The WTRU may receive an uplink bistatic sensing acknowledgment which includes information indicating a second set of (e.g., network- selected) TRPs. The WTRU may select one or more of the RS configurations from the set of RS configurations based on locations of the second set of TRPs. The WTRU may transmit one or more RSs using one or more resources of the selected one or more RS configurations.

[0007] In a representative embodiment, a network entity may send (e.g., to a WTRU) information indicating a set of RS configurations (e.g., associated with bistatic sensing). The network entity may receive an uplink bistatic sensing request which includes information indicating a first set of TRPs determined by a WTRU, an obstacle location of an obstacle, and a WTRU location of the WTRU. The network entity may send an uplink bistatic sensing acknowledgment which includes information indicating a second set of TRPs. The network entity may send location information associated with the obstacle based on reception of one or more RSs transmitted by the WTRU using one or more resources of one or more RS configurations of the set of RS configurations. For example, the network entity and/or the second set of TRPs may determine the location information (e.g., fine location of the obstacle) based on the RSs transmitted by the WTRU.

[0008] In a representative embodiment, a first WTRU may receive a sensing request which includes information indicating a first (e.g., coarse) obstacle location of an obstacle and a location of another (e.g., second) WTRU. For example, the sensing request may be received from the other WTRU. The first WTRU may determine a set of anchor WTRUs based on locations of the anchor WTRUs, the first obstacle location , and the location of the other (e.g., second) WTRU. The first WTRU may activate the set (e.g., a subset) of anchor WTRUs to perform bistatic sensing using at least one reference signal (RS) configuration. The first WTRU may receive, from at least one anchor WTRU of the set of anchor WTRUs, information indicating a second (e.g., fine) obstacle location of the obstacle based on the bistatic sensing using the at least one RS configuration.

[0009] In a representative embodiment, an anchor WTRU may receive, from another WTRU, information indicating to activate a set of anchor WTRUs for bistatic sensing using at least one RS configuration. The anchor WTRU may perform bistatic sensing using the at least one RS configuration. The anchor WTRU may send, to the other WTRU or to another anchor WTRU of the set, information indicating an (e.g., fine) obstacle location of an obstacle based on the bistatic sensing.

[0010] In a representative embodiment, a first WTRU may receive information indicating a RS configuration. The first WTRU may determine first threshold information (e.g., for a bistatic sensing coverage area) associated with bistatic sensing and second threshold information (e.g., for a monostatic sensing range) associated with monostatic sensing. The first WTRU may receive, from another (e.g., second) WTRU, information indicating any of (i) a location of the other (e.g., second) WTRU, (ii) a location of an obstacle, and (iii) a target sensing zone. The first WTRU may performing monostatic sensing or bistatic sensing (e.g., with the second WTRU) with respect to the target sensing zone according to the positioning RS configuration based on (i) a first round trip time (RTT) associated with a location of the first WTRU, the location of the obstacle, and the location of the second WTRU, (ii) a second RTT between associated with the location of the first WTRU and the location of the obstacle, (iii) the first threshold information, and (iv) the second threshold information.

[0011] In a representative embodiment, a first WTRU may receive information indicating at least one RS configuration. The first WTRU may determine a set of second WTRUs. The first WTRU may determine one or more obstacle-second WTRU pairs based on (i) round trip time (RTT) information associated with the set of second WTRUs and threshold information, and (ii) priority information associated with the obstacle and/or the set of second WTRUs. The first WTRU may send information indicating a measurement window associated with bistatic sensing to the one or more obstacle-second WTRU pairs. The first WTRU may perform, during the measurement window, bistatic sensing with the one or more second WTRUs of the determined one or more obstacle-second WTRU pairs using the at least one positioning RS configuration. [0012] In a representative embodiment, a WTRU may receive information indicating at least one positioning reference signal (RS) configuration. The WTRU may determine (e.g., bistatic) threshold information associated with sensing (e.g., minimum and maximum thresholds for bistatic sensing). The WTRU may detect an obstacle (e.g., using monostatic sensing). The WTUR may determine a second (e.g., anchor) WTRU in the vicinity of the WTRU for bistatic sensing based on the threshold information, such as based on a (e.g., bistatic) round trip time. The WTRU may send one or more RSs using first time/frequency resources associated with the positioning RS configuration. The WTRU may receive from, the other (e.g., anchor) WTRU, information indicating a (e.g., bistatically sensed) location of the obstacle.

[0013] In a representative embodiment, a first WTRU may receive, from a second WTRU, a sensing request. The sensing request may include information indicating a location of an obstacle and a location of the second WTRU. The first WTRU may determine one or more anchor WTRUs. The first WTRU may determine a group from the one or more anchor WTRUs based on (i) respective locations of the one or more anchor WTRUs and (ii) the location of the second WTRU. The first WTRU may send, to the one or more anchor WTRUs of the group, information indicating at least one positioning RS configuration. The first WTRU may determine a sub-group from the group-based on (i) respective locations of the one or more anchor WTRUs of the group and (ii) the location of the obstacle. The first WTRU may activate the sub-group for bistatic sensing. The first WTRU may receive, from at least one anchor WTRU in the sub-group, information indicating a location of the obstacle.

[0014] In a representative embodiment, a WTRU may receive positioning RS configuration information. The WTRU may determine first threshold information associated with bistatic sensing and second threshold information associated with monostatic sensing. The WTRU may receive, from a second WTRU, information indicating (i) a location of the second WTRU, (ii) a location of the obstacle, and (iii) a target sensing zone. The WTRU may perform, with the second WTRU, bistatic sensing using the positioning RS configuration information based on (i) a first round trip time (RTT) associated with a location of the first WTRU, the location of the obstacle, and the location of the second WTRU, (ii) a second RTT between associated with the location of the first WTRU and the location of the obstacle, (iii) the first threshold information, and (iv) the second threshold information.

[0015] In a representative embodiment, a WTRU may receive information indicating at least one positioning RS configuration. The WTRU may determine threshold information associated with (e.g., bistatic) sensing. The WTRU may determine one or more second WTRUs. The WTRU may determine first priority information associated with the obstacle based on a location of the first WTRU and a location of the object. The WTRU may determine second priority information associated with the obstacle based on respective locations of the one or more second WTRUs and the location of the object. The WTRU may determine one or more obstacle-second WTRU pairs based on (i) round trip time (RTT) information associated with the one or more second WTRUs and the threshold information, (ii) the first priority information, and/or (iii) the second priority information. The WTRU may send information indicating proposed measurement window information to the one or more obstacle-second WTRU pairs. The WTRU may perform bistatic sensing with the one or more second WTRUs of the determined one or more obstacle-second WTRU pairs using the at least one positioning RS configuration and the proposed measurement window.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A more detailed understanding may be had from the detailed description below, given by way of example in conjunction with drawings appended hereto. Figures in such drawings, like the detailed description, are examples. As such, the Figures (FIGs.) and the detailed description are not to be considered limiting, and other equally effective examples are possible and likely. Furthermore, like reference numerals ("ref.") in the FIGs. indicate like elements, and wherein:

[0017] FIG. 1A is a system diagram illustrating an example communications system;

[0018] FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A;

[0019] FIG. 1 C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1 A;

[0020] FIG. 1 D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A;

[0021] FIG. 2 is a system diagram illustrating an example of a monostatic sensing area;

[0022] FIG. 3 is a system diagram illustrating an example of a bistatic sensing area;

[0023] FIG. 4 is a system diagram illustrating an example of a zone of ambiguity;

[0024] FIG. 5 is a system diagram illustrating an example of two-way Round Trip Time (RTT) based obstacle sensing;

[0025] FIG. 6 is a system diagram illustrating an example of an expected monostatic RTT;

[0026] FIG. 7 is a system diagram illustrating an example of an expected bistatic RTT;

[0027] FIG. 8 is a system diagram illustrating an example of bistatic RTT thresholds and a sensing coverage area;

[0028] FIG. 9 is a system diagram illustrating another example of an expected bistatic RTT;

[0029] FIG. 10 is a system diagram illustrating an example of anchor UE selection based on threshold information;

[0030] FIG. 11 is a system diagram illustrating spatial SL-PRS configurations based on threshold information;

[0031] FIG. 12 is a system diagram illustrating differences in sensing coverage areas for uplink and downlink sensing;

[0032] FIG. 13 is a system diagram illustrating a SRSp configuration for UL bistatic sensing based on obstacle location;

[0033] FIG. 14 is a system diagram illustrating TRP selection for bistatic sensing; [0034] FIG. 15 is a system diagram illustrating group formation with respect to a reference location and group distance threshold information;

[0035] FIG. 16 is a system diagram illustrating UE roles and beam transmission patterns for obstacle detection;

[0036] FIG. 17 is a system diagram illustrating sub-group selection for sensing based on obstacle location and sub-group distance threshold information;

[0037] FIG. 18 is a signaling diagram illustrating signaling exchanges between a UE and anchor UEs for group and sub-group formation and procedures;

[0038] FIG. 19 is a system diagram illustrating sub-group modification due to obstacle movement;

[0039] FIG. 20 is a system diagram illustrating mode selection based on bistatic and monostatic thresholds information;

[0040] FIG. 21 is a flow diagram illustrating a sensing mode selection procedure for monostatic and bistatic sensing;

[0041] FIG. 22 is a system diagram illustrating a request from multiple target UEs for bistatic sensing and priority allocation;

[0042] FIG. 23 is a time and frequency resource diagram illustrating proposed measurement window configurations for different obstacles;

[0043] FIG. 24 is a signaling diagram illustrating signaling exchanges between a network, a UE and target UEs;

[0044] FIG. 25 is a flow diagram illustrating an example procedure for anchor device selection;

[0045] FIG. 26 is a flow diagram illustrating an example procedure for group-based sensing;

[0046] FIG. 27 is a flow diagram illustrating an example procedure for sensing mode selection;

[0047] FIG. 28 is a flow diagram illustrating an example procedure for prioritization of bistatic sensing;

[0048] FIG. 29 is a flow diagram illustrating an example procedure for bistatic sensing using TRPs;

[0049] FIG. 30 is a flow diagram illustrating an example procedure for bistatic sensing using TRPs;

[0050] FIG. 31 is a flow diagram illustrating an example procedure for bistatic sensing using TRPs;

[0051] FIG. 32 is a flow diagram illustrating an example procedure for bistatic sensing using TRPs;

[0052] FIG. 33 is a flow diagram illustrating an example procedure for group-based sensing;

[0053] FIG. 34 is a flow diagram illustrating an example procedure for group-based sensing;

[0054] FIG. 35 is a flow diagram illustrating an example procedure for sensing mode selection; and

[0055] FIG. 36 is a flow diagram illustrating an example procedure for prioritization of bistatic sensing.

DETAILED DESCRIPTION

[0056] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of embodiments and/or examples disclosed herein. However, it will be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other instances, well-known methods, procedures, components and circuits have not been described in detail, so as not to obscure the following description. Further, embodiments and examples not specifically described herein may be practiced in lieu of, or in combination with, the embodiments and other examples described, disclosed or otherwise provided explicitly, implicitly and/or inherently (collectively "provided") herein. Although various embodiments are described and/or claimed herein in which an apparatus, system, device and/or any element thereof carries out an operation, process, algorithm, function and/or any portion thereof, it is to be understood that any embodiments described and/or claimed herein assume that any apparatus, system, device and/or any element thereof is configured to carry out any operation, process, algorithm, function and/or any portion thereof.

[0057] Example Communications System

[0058] The methods, apparatuses and systems provided herein are well-suited for communications involving both wired and wireless networks. An overview of various types of wireless devices and infrastructure is provided with respect to FIGs. 1A-1 D, where various elements of the network may utilize, perform, be arranged in accordance with and/or be adapted and/or configured for the methods, apparatuses and systems provided herein.

[0059] FIG. 1A is a system diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail (ZT) unique-word (UW) discreet Fourier transform (DFT) spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0060] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104/113, a core network (ON) 106/115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, (e.g., at least) any of which may be referred to as a "station" and/or a "STA", may be configured to transmit and/or receive wireless signals and may include (or be) a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like, (e.g., at least) any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0061] The communications systems 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d, e.g., to facilitate access to one or more communication networks, such as the CN 106/115, the Internet 110, and/or the networks 112. By way of example, the base stations 114a, 114b may be (e.g., at least) any of a base transceiver station (BTS), a Node-B (NB), an eNode- B (eNB), a Home Node-B (HNB), a Home eNode-B (HeNB), a gNode-B (gNB), a NR Node-B (NR NB), a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

[0062] The base station 114a may be part of the RAN 104/113, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes The base station 114a and/or the base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in an embodiment, the base station 114a may include three transceivers, i.e. , one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each or any sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

[0063] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light). The air interface 116 may be established using any suitable radio access technology (RAT). [0064] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104/113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

[0065] I n an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro). [0066] I n an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access, which may establish the air interface 116 using New Radio (NR).

[0067] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., an eNB and a gNB).

[0068] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (Wi-Fi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1 X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0069] The base station 114b in FIG. 1A may be a wireless router, Home Node-B, Home eNode-B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR) to establish (e.g., at least) any of a small cell, picocell or femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106/115.

[0070] The RAN 104/113 may be in communication with the CN 106/115, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106/115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or the CN 106/115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104/113 or a different RAT. For example, in addition to being connected to the RAN 104/113, which may be utilizing an NR radio technology, the CN 106/115 may also be in communication with another RAN (not shown) employing (e.g., at least) any of a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or Wi-Fi radio technology.

[0071] The CN 106/115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104/114 or a different RAT.

[0072] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0073] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and/or other elements/peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0074] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together, e.g., in an electronic package or chip.

[0075] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in an embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In an embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

[0076] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. For example, the WTRU 102 may employ MIMO technology. Thus, in an embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0077] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0078] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0079] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium- ion (Li-ion)), solar cells, fuel cells, and the like.

[0080] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable locationdetermination method while remaining consistent with an embodiment.

[0081] The processor 118 may further be coupled to other elements/peripherals 138, which may include one or more software and/or hardware modules/units that provide additional features, functionality and/or wired or wireless connectivity. For example, the elements/peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (e.g., for photographs and/or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and/or augmented reality (VR/AR) device, an activity tracker, and the like. The elements/peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and/or a humidity sensor.

[0082] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the uplink (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the uplink (e.g., for transmission) or the downlink (e.g., for reception)).

[0083] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0084] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0085] Each of the eNode-Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink (UL) and/or downlink (DL), and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0086] The CN 106 shown in FIG. 1 C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the CN operator.

[0087] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and/or WCDMA.

[0088] The SGW 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter-eNode- B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like. [0089] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0090] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. [0091] Although the WTRU is described in FIGs. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0092] In representative embodiments, the other network 112 may be a WLAN.

[0093] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a distribution system (DS) or another type of wired/wireless network that carries traffic into and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11 z tunneled DLS (TDLS). A WLAN using an Independent BSS (I BSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an "ad-hoc" mode of communication.

[0094] When using the 802.11 ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier sense multiple access with collision avoidance (CSMA/CA) may be implemented, for example in in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0095] High throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0096] Very high throughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two noncontiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse fast fourier transform (IFFT) processing, and time domain processing, may be done on each stream separately. The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above-described operation for the 80+80 configuration may be reversed, and the combined data may be sent to a medium access control (MAC) layer, entity

[0097] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11 ah relative to those used in 802.11 n, and 802.11ac. 802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV white space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support meter type control/machine- type communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and/or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0098] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11 n, 802.11 ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or network allocation vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0099] In the United States, the available frequency bands, which may be used by 802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0100] FIG. 1 D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[O1O1] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 180b may utilize beamforming to transmit signals to and/or receive signals from the WTRUs 102a, 102b, 102c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

[0102] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., including a varying number of OFDM symbols and/or lasting varying lengths of absolute time).

[0103] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connectto gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non- standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.

[0104] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, and the like. As shown in FIG. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0105] The CN 115 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and at least one Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that (e.g., at least) any of these elements may be owned and/or operated by an entity other than the CN operator.

[0106] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b, e.g., to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, and/or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE- A, LTE-A Pro, and/or non-3GPP access technologies such as Wi-Fi.

[0107] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like. [0108] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, e.g., to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0109] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. In an embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[O11O] In view of FIGs. 1A-1 D, and the corresponding description of FIGs. 1A-1 D, one or more, or all, of the functions described herein with regard to (e.g., at least) any of: WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a- b, DNs 185a-b, and/or any other element(s)/device(s) described herein, may be performed by one or more emulation elements/devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions.

[Olli] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network. The emulation device may be directly coupled to another device for purposes of testing and/or may performing testing using over-the-air wireless communications.

[0112] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data.

[0113] Introduction

[0114] The following abbreviations and acronyms may be used herein:

ACK Acknowledgement

AoA Angle of Arrival

AoD Angle of Departure

ARFCN Absolute Radio-Frequency Channel Number

BLER Block Error Rate

BW Bandwidth

BWP Bandwidth Part

CAP Channel Access Priority

CAPC Channel access priority class

CCA Clear Channel Assessment

CCE Control Channel Element

CE Control Element

CG Configured Grant or Cell Group

CORESET Control Resource Set

CP Cyclic Prefix

CP-OFDM Conventional OFDM (relying on cyclic prefix)

CQI Channel Quality Indicator

CRC Cyclic Redundancy Check

CSI Channel State Information

CW Contention Window

CWS Contention Window Size

CO Channel Occupancy

DAI Downlink Assignment Index

DCI Downlink Control Information

DFI Downlink feedback information

DG Dynamic grant

DL Downlink

DM-RS Demodulation Reference Signal DRB Data Radio Bearer

DRX Discontinuous Reception

ECID Enhanced Cell ID lea enhanced Licensed Assisted Access ebb enhanced Mobile Broadband

FeLAA Further enhanced Licensed Assisted Access

GDoP Geometric Dilution of Precision

HARQ Hybrid Automatic Repeat Request

IM Interference Measurement

LAA License Assisted Access

LBT Listen Before Talk

LCH Logical Channel

LCP Logical Channel Priority

LBT Listen-Before-Talk

LOS Line of Sight

NLOS Non-Line of Sight

LMF Location Management Function

LPP LTE Positioning Protocol

LTE Long Term Evolution e.g., from 3GPP LTE R8 and up

MAC CE MAC Control Element

MAC Medium Access Control

MCS Modulation and Coding Scheme

MIMO Multiple Input Multiple Output

NACK Negative ACK

NAS Non-access stratum

NR New Radio

OFDM Orthogonal Frequency-Division Multiplexing

OTDOA Observed Time Difference of Arrival

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

PDU Packet Data Unit

PHY Physical Layer

PID Process ID

PO Paging Occasion PRACH Physical Random Access Channel

PRS Positioning Reference Signal

PRU Positioning Reference Unit

PSS Primary Synchronization Signal

PTRS Phase Tracking Reference Signal

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

RA Random Access (or procedure)

RACH Random Access Channel

RAR Random Access Response

RCU Radio access network Central Unit

RE Resource Element

RF Radio Frequency

RLF Radio Link Failure

RLM Radio Link Monitoring

RNTI Radio Network Identifier

RNA RAN Notification Area

RO RACH occasion

RRC Radio Resource Control

RRM Radio Resource Management

RTT Round Trip Time

RP Reception Point

RS Reference Signal

RSRP Reference Signal Received Power

RSTD Reference Signal Time Difference

RTT Round Trip Time

RSSI Received Signal Strength Indicator

RTOA Relative Time of Arrival

SDAP Service data adaptation protocol

SDU Service Data Unit

SLPP Sidelink positioning protocol

SRB Signaling Radio Bearer

SRS Sounding Reference Signal

SS Synchronization Signal SSS Secondary Synchronization Signal

SWG Switching Gap (in a self-contained subframe)

SPS Semi-persistent scheduling

SUL Supplemental Uplink

TB Transport Block

TBS Transport Block Size

TDoA Time Difference of Arrival

ToF Time of Flight

TRP Transmission-Reception Point

TSC Time-sensitive communications

TSN Time-sensitive networking

TTI Transmission Time Interval

UCI Uplink Control Information

UL Uplink

URLLC Ultra-Reliable and Low Latency Communications

WBWP Wide Bandwidth Part

WTRU Wireless Transmit Receive Unit or User Equipment (UE)

WLAN Wireless Local Area Networks and related technologies (IEEE 8O2.xx domain) [0115] In 5G NR Sensing, as defined by 3GPP SA1 , involves detecting, estimating, and monitoring conditions of the environment and/or objects within the environment (e.g., shape, size, orientation, speed, location, distances or relative motion between objects) using NR RF signals. The technologies envisioned for 5G Advance and 6G such as high carrier frequencies, large available bandwidth, large number of antennas, device-to-device communications, network densification and AI/ML all contribute to relevant information extraction with high resolution, hence enabling a highly accurate sensing.

[0116] In 3GPP, SA1 has been undertaking a study item on sensing in the context of Integrated Sensing and Communications (ISAC) including studying of the use cases, potential enhancements to the 5G systems, different sensing modes and KPIs related to sensing. For example, different modes of sensing are defined, and mainly categorized into monostatic sensing and bistatic sensing depending on the transmitter and receiver location. Monostatic sensing refers to a sensing mode with co-located transmitter and receiver and bistatic sensing refers to non-co-located transmitter and receiver.

[0117] The term ‘monostatic’ and its intended functionality are borrowed from radar where the transmitter transmits reference pulses which bounce back from a target as a backscattered signal received by the receiver to perform various radar tasks (e.g., target detection, estimation, tracking and classification). In NR, monostatic sensing utilizes the co-located transmitter and receiver and can be employed at theWTRU side or at the gNB side. The advantage of the monostatic sensing mode is only one terminal is required for sensing and the clock is synchronized. The challenge, however, is that this mode requires full duplex (FD) capabilities as it needs to transmit and receive transmitted signals simultaneously.

[0118] Full Duplex (FD) capable terminals may refer to WTRUs capable of simultaneous transmission and reception of wireless signals improving communication capacity, reducing latency An FD capable terminal is a non-limiting example of a type of WTRU that supports the simultaneous transmission and reception of wireless signals in a same frequency band. Any other type of WTRU capabilities may be substituted for the FD capability and still be consistent with this disclosure. The transmission and reception functionality in the WTRU can be (i) either allocated to different sub-bands (e.g., non-overlapping sub-band FD), or (ii) split by separate physical transmit and receive antennas (e.g., antenna group, group of antenna port(s), antenna panel) but transmitting and receiving in the same frequency band.

[0119] In NR, bistatic sensing refers to the bistatic sensing mode where a transmitter transmits the reference signals which bounces (e.g., reflects, refracts, diffracts) off the target objects and is received by the receiver. In contrast to monostatic sensing, in bistatic sensing, the transmitter and the receiver are not collocated. The architecture can consist of either combinations of the gNB(s) or the WTRU(s) as the transmitter(s) and another gNB(s) or another WTRU(s) as the receiver(s). Such setups avoid the full duplex requirements and the self-interference problem of the monostatic sensing. However, multiple terminals are required for this mode of sensing and in case of time based measurements, the terminals must be clock synchronized.

[0120] As sensing has been considered an extension of NR positioning, in certain representative embodiments, positioning reference signals, architectures, signaling frameworks, methods and protocols defined by 3GPP may be used as the baseline for NR sensing.

[0121] 3GPP Rel. 16 has defined positioning specific reference signals (PRS) for downlink and (SRSp) for uplink. For example, each of the PRS or SRSp resources may be allocated in the time/frequency OFDM grid of the transmitter. These resources may also be transmitted as directional beams. A (e.g., full) set of directional beams transmitted by a TRP or a WTRU in the same frequency may be referred to as a PRS resource set.

[0122] At each (e.g., every) positioning occasion, the PRS or SRSp configuration accounts for the time, frequency and/or spatial domain arrangement of the reference signals. In the time domain, the configuration may include the starting symbol and the total number of symbols where PRS or SRS is allocated. In the frequency domain, the configuration may include the starting resource element and the total bandwidth allocated for positioning. In the spatial domain, the PRS or SRSp resource configuration may be characterized by multiple resource sets. Each resource set may include a set of PRS or SRS beams with their resource id, the beam direction in zenith and azimuth, and the beamwidth. [0123] For accurate positioning, in any (e.g., every) positioning occasion, multiple measurements from a different TRP or WTRU is required. Hence, every positioning occasion includes PRS or SRS resource multiplexing from different TRPs or WTRUs in time, frequency and/or space. To allow for this multiplexing, for each TRP or WTRU, the PRS or SRS resources may be allocated in a staggered comb arrangement.

[0124] Further, PRS or SRSp transmission may take place in multiple positioning occasions as well. For example, between different positioning occasions, the PRS resources may be transmitted in either periodic, semi-periodic or aperiodic fashion depending upon to the positioning requirements and ability of the target WTRU. The PRS or SRSp configuration may include the periodicity to indicate these transmissions are for multiple PRS or SRSp occasions.

[0125] For example, 3GPP Rel. 16 defines different positioning methods in downlink and uplink.

[0126] In downlink positioning methods, the PRS resources from multiple TRPs are transmitted to the target WTRU. The signal propagation environment changes some of the properties of the transmitted signal such as the signal amplitude, frequency and/or phase which is measured by the WTRU as RSRP, RSTD, doppler shifts The WTRU may then infer intermediate positioning metrics, such as delay between the TRP and the WTRU with DL-TDoA or the angle with DL-AoD, using these measurements.

[0127] In uplink positioning methods, the SRSp resources may be transmitted by the WTRU to multiple TRPs. Upon reception, the TRPs measure the RSRP, RSTD, doppler shift from each of the resources. The TRP then may infer the positioning metrics such as delay with UL-TDoA or the angle with UL-AoA.

[0128] For example, a combination of both downlink and uplink method includes the TRP transmitting the PRS and the WTRU transmitting SRSp upon DL-PRS reception. This generates a two-way range between the TRP and the target WTRU eliminating the TRP-UE clock synchronization error issues.

[0129] These measurements and metrics at the WTRU or multiple TRPs may be then fused together either at the WTRU, TRP or the network to estimate the location of a target WTRU in terms of either 2D or 3D coordinates.

[0130] For example, 5G positioning architecture may include three main entities - the target WTRU, the NG-RAN (e.g., NR gNB or LTE ng-eNB TRPs), and the core network 5GC (e.g., AMF and LMF). Depending on whether the positioning is WTRU-based or WTRU-assisted, the role of each of these entities may include at least one of the following:

• requesting/transmitting positioning assistance information,

• requesting/transmitting DL-PRS/UL-SRS resources,

• measuring and/or transmitting the positioning metrics, and/or

• measuring and transmitting the final position estimate. [0131] For example, 3GPP Rel. 16 also defines various interfaces over which messages are transmitted to different entities. For example, the NG-C interface connects the NG-RAN and the 5G core network. For example, the NR/LTE Uu interface connects the WTRU and the NG-RAN.

[0132] Additionally, there are also different signaling protocols for exchanging positioning information and measurements between the entities. For example, NRPPa may be used between the NG-RAN Node and the LMF over the NG-C interface. For example, RRC may be used etween the gNB/ng-eNB and the WTRU over the NR/LTE-Uu interface. For example, LPP may be used between the WTRU and the LMF over the NG-C and NR/LTE-Uu interface.

[0133] 3GPP for NR does not currently have any special functionalities or support dedicated to sensing. However, 3GPP Rel. 16 has defined various features for NR positioning including definitions of the DL and the UL reference signals, the architecture, the protocols Sensing features can be developed by considering NR positioning features as the baseline.

[0134] In certain representative embodiments, the presence of obstacles can pose safety risk to the WTRUs in the vicinity. For example, the obstacle may be in a blind spot or too far from the WTRU to be sensed. For example, as the WTRUs may not know the when the obstacle will emerge in its vicinity, the WTRUs may not always want to allocate resources scanning the obstacles. However, WTRUs may benefit from being informed by a target WTRU regarding the presence, location of the obstacles.

[0135] In certain representative embodiments, a WTRU my perform procedures to inform other WTRUs within its vicinity as to the presence of obstacles.

[0136] In certain representative embodiments, procedures for anchor WTRU selection may be performed, such as for bistatic selection. For example, a WTRU may receive SRSp and/or SL-PRS configuration information from the network (e.g., for sensing). The configuration information may include time thresholds (e.g., threshold_min, thresholdjnax). The WTRU may detect an obstacle (e.g., via SRSp measurements from monostatic sensing). The WTRU may send a discovery message which includes information indicating (e.g., at least) any of WTRU location, obstacle location and/or sensing zone (e.g., maximum sensing radius) to any anchor WTRUs. The WTRU may receive a response from an (e.g., each) anchor WTRU with assistance information indicating (e.g., respective) anchor WTRU location. The WTRU may select an anchor WTRU for bistatic sensing, such as where the expected RTT (e.g., determined based on the anchor WTRU location and obstacle location) is above a threshold (e.g., threshold_min or otherwise associated with being, outside of an ambiguity range) and below another threshold (e.g., thresholdjnax or otherwise below a maximum range). The WTRU may send a request for bistatic sensing to the selected anchor WTRU(s). The request may include information indicating at least a measurement window (e.g., start time, duration). The WTRU may transmit SL-PRS configuration information to the anchor WTRU(s) based on the anchor WTRU(s) sending a “Yes” reply. The SL-PRS configuration information (e.g., spatial Tx direction of SL-PRS, order of SL-PRS transmission) may be determined by a sensing coverage area, such as may be associated with the threshold_min and thresholdjnax. The WTRU may transmit the SL-PRS configuration information to the anchor WTRU(s) and the WTRU may receive a report with obstacle location information from the anchor WTRU(s).

[0137] In certain representative embodiments, procedures for group-based sensing may be performed. For example, a WTRU (e.g., a server WTRU) may receive a request for sensing from a WTRU (e.g., target WTRU which is in out-of-coverage) with obstacle location and WTRU location. The WTRU may send a discovery message with the obstacle location. The WTRU may receive a response from any anchor WTRU(s) with anchor WTRU locations. The WTRU may add an anchor WTRU to the group if its distance from the target WTRU location is below a threshold (e.g., within a sub-group distance threshold). The WTRU may configure the group with SL-PRS configuration information (e.g., SL-PRS resource I D(s), measurement windows). The WTRU may form a sub-group of WTRUs for bistatic sensing based on the distance of the obstacle from the WTRU in the sub-group being below a threshold. For example, the WTRU may determine WTRU roles (e.g., Tx WTRU, Rx WTRU) for bistatic sensing. The WTRU (e.g., via groupcast) may activate the sub-group (e.g., containing a Tx WTRU and at least one Rx WTRU) by sending bistatic sensing assistance information with at least sub-group anchor WTRU locations and WTRU roles to the WTRUs in the sub-group. The WTRU may receive a measurement report with obstacle location from a WTRU in the subgroup.

[0138] In certain representative embodiments, the WTRU may receive a request to deactivate from a WTRU (e.g., a Rx WTRU) in the sub-group. The WTRU may determine to, such as based on periodic broadcast information of anchor WTRU location, remove a WTRU in the sub-group if its distance from an obstacle location is above a threshold. The WTRU may determine to add a new WTRU(s) in the sub-group from the group if its distance to the obstacle is below a threshold. The WTRU (e.g., via groupcast) may activate the modified sub-group and send modified assistance information. The WTRU may determine to deactivate the sub-group, such as where the number of WTRUs in the sub-group is below a threshold.

[0139] In certain representative embodiments, procedures for sensing mode selection may be performed, such as by an anchor WTRU. For example, a WTRU (e.g., anchor WTRU) may receive SRSp and SL-PRS configuration information from the network for sensing. The configuration information may include bistatic time thresholds (e.g., threshold_min, thresholdjnax), a monostatic threshold, and distance threshold. The WTRU may receive a discovery message for obstacle sensing from a target WTRU with target WTRU location, obstacle location and target WTRU sensing zone information. The WTRU may respond with its location, such as where its distance to the obstacle is below the distance threshold. The WTRU may receive a request for bistatic sensing from a target WTRU with a measurement window. The WTRU may determine to assist the target WTRU in bistatic sensing and responds “Yes”, such as where (i) the expected bistatic RTT is above a threshold (e.g., threshold_mi n or otherwise outside of an ambiguity range) and below another threshold (e.g., thresholdjnax or otherwise below a maximum range), or (ii) the expected monostatic RTT is above the monostatic RTT threshold. The WTRU may respond “No” and determine to perform monostatic sensing if the expected monostatic RTT is below the monostatic threshold. The WTRU may respond “No” and determines not to sense if the expected bistatic RTT and monostatic RTT are above the thresholdjnax and monostatic threshold, respectively.

[0140] For example, the WTRU may configure the resources for transmission and/or reception. If the WTRU’s response is “Yes”, the WTRU activates the measurement window and receives the SL-PRS in SL- PRS resources for bistatic sensing. If the WTRU’s response is “No” and it determines to perform monostatic sensing, the WTRU configures the SRSp resources and transmits and receives SRSp in the SRSp resources. [0141] In certain representative embodiments, procedures for bistatic obstacle prioritization for multiple sensing requests may be performed. For example, a WTRU (e.g., anchor WTRU) may receive SL-PRS configuration information from the network for sensing including time thresholds (e.g., thresholdjnin, thresholdjnax). The (e.g., anchor) WTRU may receive a discovery message from multiple WTRUs. For example, the discovery message may include information indicating (e.g., at least) any of WTRU locations, sensing zones and/or obstacle locations. The WTRU may respond to (e.g., at least) any of target WTRU(s), such as based on its distance to the obstacle being below a threshold. The WTRU may receive a request for bistatic sensing from the target WTRUs with the measurement window(s). The WTRU may determine an obstacle priority (e.g., based on the target WTRU, obstacle and its locations) from the WTRU and target WTRU’s perspective. The WTRU may select one or more obstacle and target WTRU pairs.

[0142] For example, the WTRU may select an obstacle and target WTRU pair based on (e.g., at least) any of: (i) an expected RTT of the pair is above a threshold (e.g., threshold_min or otherwise outside of an ambiguity range) and below another (e.g., thresholdjnax or otherwise below a maximum range); (ii) the obstacle’s priority from the WTRU’s perspective is above a threshold; and/or (iii) the obstacle’s priority from the target WTRU’s perspective is above a threshold. For each obstacle in the selected obstacle and target WTRU pairs, the WTRU may determine a proposed measurement window. The proposed measurement window may be based on the received measurement windows of the target WTRUs paired with the obstacle. [0143] For example, the may WTRU respond “Yes” to each target WTRU in a pair (e.g., each pair) and include with the “Yes” response the proposed measurement window (e.g., for bistatic sensing) determined for the obstacle the WTRU is paired with. When the (e.g., anchor) WTRU receives an acknowledgement to the “Yes” from at least one target WTRU paired with the obstacle, the (e.g., anchor) WTRU may activate the proposed measurement window and receive SL-PRS in the SL-PRS resources from the target WTRUs (e.g., during the activated measurement window). [0144] Common Terminology

[0145] As used herein, a “TRP” may be used interchangeably with “gNB” or “PRU”.

[0146] As used herein, a “target WTRU” maybe used interchangeably with “sensing WTRU”.

[0147] As used herein, a “network” may refer to (e.g., at least) any of the AMF, LMF and/or gNB.

[0148] As used herein, a “location” may be used interchangeably with “position”.

[0149] As used herein, a “measurement occasion” may be defined as an instance where the WTRU measures one or more (e.g., different) positioning metrics (e.g., RSRP, ToF).

[0150] As used herein, a “RS” may refer to (e.g., at least) any of the positioning and reference signals, such as for PRS, SRSp, CSI-RS, DM-RS, SSB

[0151] As used herein, a WTRU may receive one or more (pre)configured threshold from the network (e.g., LMF, gNB), such as via downlink a physical channel (e.g., PDSCH, PDCCH) and/or via lower or higher layer signalling (e.g., UCI, MAC-CE, RRC and/or LPP message).

[0152] As used herein, a WTRU may receive a (pre)configured threshold(s) from the WTRU (e.g., server WTRU), such as via sidelink physical channel (e.g., PDSCH, PDCCH) and/or via lower or higher layer signalling (e.g., SCI, SL-MAC-CE, PC5-RRC message).

[0153] As used herein, an effective bandwidth may be defined as a total amount of frequency resources (e.g., in Hz) used for sensing purposes. For example, for a comb-6 configuration with 50 RBs of bandwidth, the effective bandwidth may be calculated as

.

[0154] As used herein, a relative velocity may be defined as a velocity of an object/UE with respect to another WTRU. The relative velocity may define the time rate of change of relative position of the obstacle/UE with respect to another WTRU.

[0155] As used herein, a RTT may be defined as total signal propagation time (e.g., ToF) between the transmitter and the receiver through a single bounce from the obstacle. The RTT may refer to the propagation time between a TRP and a WTRU, or between a WTRU and a WTRU (e.g., SL-RTT).

[0156] As used herein, a coverage angle refers to an angle covering a sector.

[0157] As used herein, an expected AoD refers to an angle between the transmitter and the (e.g., coarse) obstacle location with respect to the orientation of the transmitter.

[0158] As used herein, an expected AoA refers to angle between the (e.g., coarse) obstacle location and the receiver with respect to the orientation of the receiver.

[0159] As used herein, a sensing window may be defined as a time period that may be reserved for sensing purposes (e.g., sensing RS transmission, reception, sensing procedures measurement, estimation, reporting). It may be characterized by (e.g., at least) any of start time, stop time, duration, offset [0160] As used herein, a measurement window may be defined as a time period that may be reserved for RS measurement. It may be characterized by (e.g., at least) any of start time, stop time, duration, periodicity, offset

[0161] As used herein, an LMF is a non-limiting example of a node or entity (e.g., network node or entity) that may be used for or to support positioning. Any other node or entity (e.g., server WTRU) may be substituted for LMF and still be consistent with this disclosure.

[0162] As used herein, a server WTRU may refer to a WTRU that may be able to perform at (e.g., at least) any of the following tasks: (i) receive and authorize request from WTRUs for positioning, sensing tasks; (ii) select the anchor WTRUs for positioning/sensing; (iii) configure the WTRUs with positioning resources (e.g., SL-PRS resources, SRSp resources); (iv) select the positioning method (e.g., RTT, TDoA); (v) compute the position of the target WTRU, obstacle based on the (reported) measurements; and/or (vi) forward the measurement report to the reporting entities (e.g., WTRUs). Any other node or entity used for or to support positioning (e.g., LMF) may be substituted for server WTRU and still be consistent with this disclosure.

[0163] As used herein, a sensing time resolution, (e.g., measured in terms of seconds, number of symbols, number of slots, number of frames or number of subframes) may refer to the time granularity with which the entity (e.g., WTRU) may measure the time related positioning metrics (e.g., RTT). It may depend on the ability of the WTRU to process (e.g., compute FFT) large frequency domain samples.

[0164] As used herein, a sensing frequency resolution (e.g., measured in terms of Hz, number of REs, number of RBs) may refer to the frequency granularity with which an entity (e.g., WTRU) may measure the frequency of the received RS. Sensing frequency resolution may depend on the number of OFDM symbols used in each measurement occasion.

[0165] Configurations for RS Sensing

[0166] Configurations for DL-PRS

[0167] In certain representative embodiments, a DL-PRS configuration may include information indicating (e.g., at least) any of the following parameters: number of symbols, transmission power, number of DL-PRS resources included in DL-PRS resource set, muting pattern for DL-PRS (for example, the muting pattern may be expressed via a bitmap), periodicity, type of PRS (e.g., periodic, semi-persistent, or aperiodic), slot offset for periodic transmission for DL-PRS, vertical shift of DL-PRS pattern in the frequency domain, time gap during repetition, repetition factor, RE (resource element) offset, comb pattern, comb size, spatial relation, QCL information (e.g., QCL target, QCL source) for DL-PRS, number of PRUs, number of TRPs, Absolute Radio-Frequency Channel Number (ARFCN), subcarrier spacing, expected RSTD, uncertainty in expected RSTD, start Physical Resource Block (PRB), bandwidth, BWP ID, number of frequency layers, start/end time for PRS transmission, on/off indicator for PRS, TRP ID, PRS ID, cell ID, global cell ID, PRU ID, and/or applicable time window. For example, a WTRU may apply a PRS configuration under a condition that the current time is within the applicable time window. “ID” may be used interchangeably with “index”.

[0168] Configurations for SRS for positioning

[0169] In certain representative embodiments, a SRS for positioning (SRSp) or SRS configuration may include information indicating (e.g., at least) any of: resource ID; comb offset values, cyclic shift values; start position in the frequency domain; number of SRSp symbols; shift in the frequency domain for SRSp; frequency hopping pattern; type of SRSp (e.g., aperiodic, semi-persistent or periodic); sequence ID used to generate SRSp, or other IDs used to generate SRSp sequence; spatial relation information, indicating which reference signal (e.g., DL RS, UL RS, CSI-RS, SRS, DM-RS) or SSB (e.g., SSB ID, cell ID of the SSB) the SRSp is related to spatially where the SRSp and DL RS may be aligned spatially; QCL information (e.g., a QCL relationship between SRSp and other reference signals or SSB); QCL type (e.g., QCL type A, QCL type B, QCL type D); resource set ID; list of SRSp resources in the resource set; transmission power related information; pathloss reference information which may contain index for SSB, CSI-RS or PRS; periodicity of SRSp transmission; and/or spatial information such as spatial direction information of SRSp transmission (e.g., beam information, angles of transmission), spatial direction information of DL RS reception (e.g., beam ID used to receive DL RS, angle of arrival). As used herein, the term “ID” may be used interchangeably with “index”.

[0170] Configurations for SL-PRS

[0171] In certain representative embodiments, a SL-PRS configuration may include information indicating (e.g., at least) any of the following parameters: number of symbols, transmission power, number of SL-PRS resources included in SL-PRS resource set, muting pattern for SL-PRS (for example, the muting pattern may be expressed via a bitmap), periodicity, type of SL-PRS (e.g., periodic, semi-persistent, or aperiodic), slot offset for periodic transmission for SL-PRS, vertical shift of SL-PRS pattern in the frequency domain, time gap during repetition, repetition factor, RE (resource element) offset, comb pattern, comb size, spatial relation, QCL information (e.g., QCL target, QCL source) for SL-PRS, number of PRUs, number of TRPs, Absolute Radio-Frequency Channel Number (ARFCN), subcarrier spacing, expected RSTD, uncertainty in expected RSTD, start Physical Resource Block (PRB), bandwidth, BWP ID, number of frequency layers, start/end time for PRS transmission, on/off indicator for SL-PRS, TRP ID, SL-PRS ID, cell ID, global cell ID, PRU ID, and/or applicable time window. For example, a WTRU may apply a SL-PRS configuration under a condition that the current time is within the applicable time window.

[0172] Measurements

[0173] In certain representative embodiments, a RTT may be defined as the single bounce total round trip time or time of flight between the transmitter, the obstacle and the receiver. [0174] In monostatic sensing, a monostatic RTT may be defined as the delay corresponding to the two- way range between the transmitting/receiving entity (e.g., a full duplex WTRU/TRP) and the obstacle. In bistatic sensing, a bistatic RTT may be defined as the delay corresponding to the single bounce range between the transmitting entity (e.g., WTRU/TRP), the obstacle, and the receiving entity (e.g., WTRU/TRP). The term ToF may be alternatively used instead of RTT in this disclosure. If the transmitting and the receiving entities are both WTRUs (e.g., co-located, non-co-located), the term SL-RTT may be alternatively used instead of RTT in this disclosure.

[0175] In certain representative embodiments, a RTT may be measured through transmit and receive time stamps. A WTRU may measure the time stamps in terms of (e.g., at least) any of symbol index, slot index, frame index Time stamps may either be absolute or relative. An absolute time may refer to the exact transmit and receive time of the sensing RS (e.g., Tx time: 5^th slot, Rx time 6^th slot, RTT = Rx timestamp - Tx timestamp = 1 slot). A relative time may refer to the difference in transmit and receive time of the positioning RS (e.g., ToF = 1 slot).

[0176] Obstacle Detection

[0177] In certain representative embodiments, a WTRU may detect an obstacle during (e.g., at least) any of the communication phase, positioning phase, and/or a dedicated sensing phase. For example, a WTRU may detect an obstacle during the communication or positioning phase.

[0178] In certain representative embodiments, a WTRU may (e.g., also) detect an obstacle during communication based on at least one of the following conditions:

• Measured delay spread from a TRP above a (pre)configured threshold,

• Measured doppler shift in the RS above a (pre)configured threshold,

• Decrease in RSRP of the RS above a (pre)configured threshold,

• Change in measured doppler shift of the RS above a (pre)configured threshold,

• Decrease in SNR/SINR of the received RS above a (pre)configured threshold, and/or

• Increase in re-transmission request above a (pre)configured threshold.

[0179] In certain representative embodiments, a WTRU may detect an obstacle during a positioning process based on at least one of the following conditions:

• LoS/NLoS ID of the communicating TRP(s) below a (pre)configured threshold,

• Measured RSRP from the NLoS TRP(s) above a (pre)configured threshold,

• Change in LoS/NLoS ID of the TRP(s) from LoS to NLoS above a (pre)configured threshold,

• Total measured time measurement(s) corresponding to the same PRS resource ID(s) above a (pre)configured threshold,

• The difference between measured AoA(s) corresponding to the same received PRS resource I D(s) above a (pre)configured threshold, and/or • The RSRP difference between the PRS resource in multiple measurement occasions above a (pre)configured threshold.

[0180] In certain representative embodiments, a WTRU may be configured for monostatic sensing and may detect an obstacle. For example, procedures for initiation and detection of obstacle location with monostatic sensing are provided below.

[0181] In certain representative embodiments, a WTRU may be configured with SRSp for monostatic sensing.

[0182] In one example, the WTRU may send a request to the network (e.g., LMF, gNB, entity that configures reference signals to the WTRU) for SRSp configuration for sensing in the uplink physical channels, such as PUSCH or PUCCH, via higher layer signaling (e.g., MAC-CE or RRC), and/or via LPP messages.

[0183] In one example, the WTRU may receive the SRSp configuration from the network (e.g., LMF, gNB). [0184] In one example, the WTRU may receive sensing assistance information and exchange capability information with the network as a part of the initial configuration. These messages and exchanges may take place semi-statically (e.g., via the LPP or RRC message).

[0185] In one example, the WTRU may receive the sensing assistance information from the network which includes at least the spatial information of the configured SRSp resource sets and resources including the angles (e.g., azimuth, zenith) and the beamwidth.

[0186] In another example, the WTRU and the network may also transmit (e.g., exchange) capability information. A capability message may include (e.g., at least) any of the following information:

• The WTRU’s full duplexing capabilities (e.g., whether simultaneous transmission and reception of wireless signals is applicable in the same frequency including sub-band overlapping or nonoverlapping cases, any parameter(s) related to necessary time gap for the Tx/Rx switching, and/or parameter(s) related to the number of antenna panels, antenna groups and group of antenna ports applicable for the simultaneous Tx/Rx),

• The WTRU’s measurement capabilities (e.g., ability to measure doppler frequency shift, the maximum sensing range, the sensing time resolution, the sensing frequency resolution), and/or

• The WTRU’s reporting capabilities (e.g., ability to measure, estimate and/or report the doppler frequency shifts, ability to measure, estimate and/or report its position and/or orientation periodically/aperiodically).

[0187] In certain representative embodiments, the WTRU may be a positioning reference unit (PRU). For example, a PRU may be a WTRU whose location is known to the network and/or peer WTRU(s) (e.g., target WTRU, anchor WTRU, server WTRU) where the WTRU has the capability to provide SL-PRS configurations to WTRUs, receive measurement reports from WTRUs, determine the locations of WTRUs and/or schedule resources for SL-PRS transmission. The WTRU may transmit (e.g., exchange) capability information with the network and/or peer WTRU(s).

[0188] In certain representative embodiments, a WTRU may initiate monostatic sensing for obstacle detection.

[0189] In one example, the WTRU may receive an indication from the network to initiate the sensing process, such as through a WTRU dedicated DCI, MAC-CE, RRC, and/or LPP message. This indication may either be triggered by the WTRU or initiated by the network.

[0190] In one example, the WTRU may trigger the sensing process due to it implicitly sensing obstacles in its vicinity. The conditions when it may determine to trigger the sensing process were mentioned above (e.g., above (pre)configured threshold loss in communication performance, above a (pre)configured threshold loss in positioning performance).

[0191] In another example, sensing may also be triggered by the network based on identification of an obstacle in a location which is below a (pre)configured threshold distance to the WTRU.

[0192] In one example, the WTRU may receive a sensing window with the indication. The sensing window may be characterized by (e.g., at least) any of the following parameters:

• Start or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point), and/or

• Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds).

[0193] In certain representative embodiments, a WTRU may detect and locate an obstacle with monostatic sensing.

[0194] In one example, the WTRU may initiate monostatic sensing with configured SRSp resources upon the start of sensing window. Assuming the WTRU is equipped with full duplex capabilities, it may transmit and receive the SRSp resources using separate but co-located transmit and receive antenna panels.

[0195] In one example, the WTRU may detect an obstacle with monostatic sensing based on the measurements (e.g., RSRP, RTT, AoA) on its (e.g., reflected) SRSp resources based on at least one of the following conditions:

• The measured RSRP of the SRSp resources above a (pre)configured threshold,

• The difference between the measured RSRP corresponding to the same SRSp resource(s) in multiple measurement occasions above a (pre)configured threshold,

• The measured RTT of the resource(s) below a (pre)configured threshold,

• The difference between the measured RTT between multiple measurement occasion above a (pre)configured threshold, and/or

• The difference between the AoD(s) of the transmitted resource(s) and the AoA(s) of the received resource(s) below a (pre)configured threshold. [0196] In one example, the WTRU may determine the location of the obstacle and/or the associated uncertainty range from the measurements. The WTRU may use a combination of measurements (e.g., RTT, AoD, AoA) to determine the obstacle location.

[0197] I n one example, the WTRU may also measure the velocity associated with the obstacle. The WTRU may determine the velocity based on the measured doppler frequency shift of corresponding to the received SRSp resources associated with the obstacle.

[0198] In certain representative embodiments, a WTRU may determine uncertainties in obstacle location. [0199] In one example, an uncertainty related to an obstacle location and/or velocity may be defined as the range of possible values where a true value may lie within. In one example, a 2D location uncertainty may be defined as (x±m, y±n), where ‘m’ and ‘n’ may be defined as the horizontal ‘x’ and vertical ‘y’ uncertainty ranges, respectively. It indicates that the true horizontal and vertical values of the location may lie within the range [x-m, x+m] and [y-n, y+n] respectively.

[0200] In one example, the location and velocity uncertainties may be measured in terms of meters and meter/seconds, respectively.

[0201] In one example, the WTRU may calculate the uncertainty in obstacle location and/or velocity to perform anchor WTRU selection, WTRU selection, resource allocation for obstacle location and/or velocity estimation

[0202] In one example, the WTRU may indicate to the network the source of the uncertainty associated with the obstacle location and/or velocity. The source of the error may include at least one of the following:

• The error is associated with positioning method associated with the obstacle location and/or velocity: o For example, the number of entities (e.g., anchor WTRUs, TRPs) for location and/or velocity measurements (e.g., transmission, reception) is below a (pre)configured threshold, o For example, the obstacle location was obtained with the RTT measurements from less than N (e.g., 3) monostatic WTRUs, o For example, the obstacle location and was obtained due blockage detection between a WTRU and the TRP during the communication procedure (e.g., decrease in SNR/SINR above a (pre)configured threshold), o For example, the obstacle location was obtained due multipath detection during the positioning procedure (e.g., RSRP of the multipath component above a (pre)configured threshold, decrease in LoS/NLoS ID between multiple measurement occasions above a (pre)configured threshold), o For example, the obstacle location was obtained with monostatic sensing RTT measurements from multiple WTRUs with WTRU locations causing a high GDoP (e.g., WTRU locations co-linear to the obstacle); • The error is associated with the Tx/Rx capabilities and RS signal properties: o For example, for time-based methods (e.g., RTT), the effective bandwidth of the RS (e.g. PRS, SRSp) is below a (pre)configured threshold, o For example, for time-based methods (e.g., RTT) and angle-based method (e.g., AoD, AoA), the beamwidth of the RS (e.g., PRS, SRSp) is above a (pre)configured threshold, o For example, for time-based method (e.g., RTT) and angle-based method (e.g., AoD, AoA), the number of the transmitting and/or the receiving antennas is below a (pre)configured threshold, o For example, the total number of allocated OFDM symbols in a resource is below a (pre)configured threshold;

• The error is associated with uncertainty in WTRU location(s)/velocities: o For example, the uncertainty in the locations of the WTRU and/or the anchor WTRU(s) participating in the measurements is above a (pre)configured threshold, o For example, the uncertainty in the velocities of the WTRU and/or the anchor WTRU(s) participating in the measurements is above a (pre)configured threshold; and/or

• The error is associated with time/frequency/phase synchronization: o For example, for time and/or frequency-based methods (e.g., RTT, doppler shift ), the WTRU(s)/TRP(s) participating in the measurement are time synchronized to the same source (e.g., TRP), and/or time synchronized to the sources with known clock offset

[0203] In one example, the WTRU may be configured by the network with an indication of the error sources and/or the weights associated with each error source to determine the uncertainty in the obstacle location and/or velocity.

[0204] In another example, the WTRU may autonomously determine the weights associated with the error sources based on the measurements.

[0205] In certain representative embodiments, a WTRU may report an obstacle (e.g., obstacle information) to the network.

[0206] In one example, a WTRU may be configured to report an obstacle location to the network based on (e.g., at least) any of the following trigger conditions which may be configured by the network:

• a distance between the WTRU and the obstacle location is below a (pre)configured threshold,

• a determined obstacle priority for the WTRU is above a (pre)configured threshold,

• a measured RSRP of the obstacle is above a (pre)configured threshold,

• a velocity of the obstacle is above a (pre)configured threshold,

• a WTRU’s coverage changes from out-of-coverage to in-coverage, and/or a WTRU receives a request from the network to report the location of the obstacle periodically and/or when it detects the obstacle.

[0207] In another example, a WTRU may be configured by the network to report an obstacle location at a configured reporting time instance. The reporting time configuration may (e.g., at least) any of the following:

• Reporting time instance (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point); and/or

• Reporting periodicity (e.g., in terms of number of symbols, slots, frames, subframes, seconds).

[0208] In another example, a WTRU may be configured to report an obstacle location within a time window (e.g., N slots, N seconds, N subframes, N frames, N symbols) from a time (e.g., instance) the WTRU determines or detects the presence of the obstacle.

[0209] In one example, in case of reporting at a configured time instance, if the WTRU has not detected an obstacle, the WTRU may:

• miss the reporting in the scheduled instance, or

• report no obstacle detected in the measurement report.

[0210] In one example, the WTRU, upon fulfillment of the reporting conditions, may report (e.g., at least) any of the following:

• UE location and/or the associated uncertainty range,

• obstacle location(s) and/or the associated uncertainty range(s),

• obstacle velocity and/or the associated uncertainty range,

• measurements (e.g., measured RSRP, AoD, AoA, RTT),

• SRSp resource I D(s) associated with the measurements,

• SRSp resource set I D(s) associated with the measurements, and/or

• Measurement time stamp

[0211] In certain representative embodiments, a WTRU may use (e.g., at least) any of DCI, MAC-CE, RRC, and/or LPP messages to perform obstacle measurement reporting.

[0212] Obstacle Priority

[0213] In certain representative embodiments, the WTRU (e.g., target WTRU, anchor WTRU) may determine the priority of an obstacle with respect to its location and/or the location of any other entities (e.g., anchor WTRU(s)).

[0214] In one example, the priority may be indicated categorically (e.g., low, medium, high) or numerically (e.g., 0, 0.1 , ..., 1). The WTRU may prioritize the measurements related to the obstacle. Prioritization may be dependent on (e.g., at least) any of the following:

• UE location and/or the associated uncertainty range,

• UE velocity and/or the associated uncertainty range, • Obstacle location and/or the associated uncertainty range, and/or

• Obstacle velocity and/or the associated uncertainty range.

[0215] In one example, the WTRU may use a combination of the above factors to decide and indicate the priority of the obstacle.

[0216] In one example, the WTRU may determine and/or indicate a high priority to the obstacle in case of at least one of the following conditions:

• the distance between the WTRU and the obstacle is below a (pre)configured threshold,

• the velocity of the obstacle is above a (pre)configured threshold,

• the velocity of the WTRU is above a (pre)configured threshold,

• the relative velocity between the WTRU and the obstacle is above a (pre)configured threshold,

• the uncertainty in the obstacle location is above a (pre)configured threshold,

• the uncertainty in WTRU location is above a (pre)configured threshold, and/or

• the uncertainty in WTRU velocity is above a (pre)configured threshold

[0217] In one example, the WTRU may determine and/or indicate a low priority to the obstacle if the conditions mentioned above are not satisfied.

[0218] In another example, the WTRU may receive the obstacle priority from the network based on the reported WTRU location and/or the associated uncertainty range, obstacle location and/or the associated uncertainty range , and/or velocity and/or the associated uncertainty range.

[0219] In one example, a target WTRU may determine and allocate resources (e.g., time, frequency) based on its priority. The WTRU may allocate an above threshold time (e.g., no. of symbols, no. of resources, periodicity) and an above threshold frequency (e.g., no of RBs, comb size) resources for an obstacle with priority above a (pre)configured threshold.

[0220] In one example, the WTRU may allocate a below threshold time and/or frequency resources otherwise, such as for an obstacle with priority below a (pre)configured threshold.

[0221] Common Principles and Observations

[0222] In certain representative embodiments, RTT has been considered as the main method of sensing as it plays an important role in not only locating the obstacle but also for the determination of the sensing coverage area, transmission parameters, selection of anchor WTRU(s), and/or indication of configured resources

[0223] In certain representative embodiments, a WTRU may perform RTT-based obstacle positioning.

[0224] For example, RTT may correspond to the absolute difference between RS transmission time and reception time. In monostatic sensing, the ToF between the terminal (e.g., WTRU, gNB) and the obstacle may correspond to the RTT from the WTRU to the obstacle and back to the WTRU. In bistatic sensing, the RTT between the transmitting terminal, obstacle, and the receiving terminal may correspond to the total time taken for the RS to propagate the single bounce path between the two terminals and the obstacle.

[0225] In certain representative embodiments, a WTRU may perform RTT-based obstacle positioning in, or using, monostatic sensing.

[0226] FIG. 2 is a system diagram illustrating an example of a monostatic sensing area for a given RTT.

[0227] For monostatic sensing, a RTT measurement (e.g., T_MS-) from an object (e.g., obstacle) 202 corresponds to the object location in a circle 204 with a center at the WTRU location and a radius R_MS = a distance corresponding to one-way ToF between the WTRU 102 and the object 204 as in FIG. 2. [0228] In one example, a monostatic sensing WTRU 102 may transmit and receive an RS and measure the positioning metrics (e.g., RTT, AoD, AoA, doppler shift ). In one example, the monostatic RTT-based obstacle positioning may either be WTRU-based or WTRU-assisted.

[0229] For example, for WTRU-based monostatic RTT-based obstacle positioning, the WTRU 102 may measure the monostatic RTT measurements and obtain the range of the obstacle. In another example, the WTRU may measure a combination of RTT and AoD and/or AoA, and determine the location coordinates of the obstacle.

[0230] For example, for WTRU-assisted monostatic RTT-based obstacle positioning, the network may obtain the obstacle location assisted by the WTRU 102 for RTT-based obstacle positioning. In one example, the network may obtain the RTT measurements from multiple monostatic sensing WTRUs to determine the location coordinates of the obstacle (e.g., via circle-based trilateration).

[0231] In one example, the monostatic RTT may be expressed in terms of seconds, number of symbols, number of slots, number of frames, and/or number of subframes.

[0232] In certain representative embodiments, a WTRU 102 may perform RTT-based obstacle positioning in, or using, bistatic sensing.

[0233] FIG. 3 is a system diagram illustrating an example of a bistatic sensing area.

[0234] For bistatic sensing, a RTT measurement (e.g. _BS) may correspond to an ellipse 302 with two foci (e.g., the Tx and the Rx locations) with a major axis as R_BS = C. T_BS. Considering the same RTT measurement in both monostatic and bistatic modes (e.g., T_MS = TBS') the R_BS would be equal to 2R_MS as in FIG. 3.

[0235] FIG. 4 is a system diagram illustrating an example of a zone of ambiguity (e.g., ambiguity zone) 402.

[0236] In bistatic sensing with WTRUs 102a and 102b, an ambiguous RTT may be defined as the delay duration where the receiver cannot differentiate the measured delay between delay of the path reflected from the obstacle from the direct LoS delay. This is caused due to the granularity in delay estimation due to limited bandwidth. Specifically, if the bistatic ToF _BS < _TX-RX + AT , where _TX-RX = d/c represents the direct LoS delay and AT = represents the delay resolution, where K is the total number of used subcarriers

and A is the subcarrier spacing. This region is also represented by an ellipse 402, as shown in FIG. 4 where the obstacle may not be located if within the ellipse region.

[0237] In one example, for bistatic sensing, an entity (e.g., TRP, WTRU) may transmit the RS received by another entity (e.g., another TRP, WTRU) and measure the positioning metrics (e.g., RTT, AoD, AoA, doppler shift ). In one example, the bistatic RTT-based obstacle positioning may either be WTRU-based, or network- assisted.

[0238] In one example, the bistatic RTT may be expressed in terms of seconds, number of symbols, number of slots, number of frames, and/or number of subframes.

[0239] A bistatic RTT may be determined based on Rx-Tx time at WTRU and TRP (or gNB) for networkbased bistatic RTT. For example, the WTRU may report WTRU Rx-Tx time based on transmission time of SRSp and reception time of DL-PRS where the reception or transmission time may be based on timing of reception or transmission of symbol(s), slot(s), subframe(s), and/or frame(s) that contain SRS or DL-PRS, respectively.

[0240] A bistatic RTT for SL based sensing may be determined based on Rx-Tx time at the target WTRU and anchor WTRU, for example. For example, the WTRU may report WTRU Rx-Tx time based on transmission time of SL-PRS and reception time of SLPRS where the reception or transmission time may be based on timing of reception or transmission of symbol(s), slot(s), subframe(s), and/or frame(s) that contain SRS or PRS, respectively.

[0241] In certain representative embodiments, two-way RTT based obstacle positioning in bistatic sensing may be performed.

[0242] FIG. 5 is a system diagram illustrating an example of two-way RTT-based obstacle sensing.

[0243] For two-way sensing methods, a WTRU may receive a configured DL-PRS in the downlink and measure the configured metrics (e.g., RTT, AoA). For example, as illustrated in Figure 4, the WTRU 102 may receive the DL-PRS resources transmitted by the TRP 502 and measure the Rx time ‘t2’. The WTRU 102 may transmit the configured SRSp resources in the uplink and record the transmit time, AoD For example, as in FIG. 5, the WTRU may transmit the SRSp resources and measure the transmit time 3’. The WTRU may report the measurements (e.g., DL-PRS Rx time, SRSp Tx time, DL-AoA, UL-AoD) to the network and receive the obstacle location of the object 202. The order of DL and UL in the above figure may be interchanged, or performed simultaneously in some cases (e.g., full duplex WTRUs).

[0244] Expected Monostatic and Bistatic RTT and Uncertainties

[0245] In certain representative embodiments, based on the transmitter location, (e.g., coarse) obstacle location and the receiver location, the WTRU (e.g., target WTRU, anchor WTRU, server WTRU) may determine the expected monostatic and bistatic RTTs. [0246] As used herein, the term “expected” is used for monostatic and bistatic RTTs to indicate that the RTT may be determined based on a coarse knowledge of the obstacle location. This is as opposed to the monostatic and bistatic RTTs that may be calculated based on the knowledge of an exact obstacle location or obstacle location where the uncertainty is below a (pre)configured threshold.

[0247] FIG. 6 is a system diagram illustrating an example of an expected monostatic RTT.

[0248] For example, an expected monostatic RTT may be defined as the expected round trip propagation time taken for the transmitted RS to bounce off the obstacle 202 and be received by the monostatic WTRU 102 in a single bounce path. The expected monostatic RTT may be computed as y, where d is the distance between the WTRU 102 and the obstacle 202 and c is the speed of light constant as in FIG. 6.

[0249] In one example, the expected monostatic RTT may be expressed in terms of seconds, number of symbols, number of slots, number of frames, and/or number of subframes.

[0250] FIG. 7 is a system diagram illustrating an example of an expected bistatic RTT.

[0251] In one example, the expected bistatic RTT may be defined as the expected one-way propagation time for the RS to traverse the distance between the transmitting WTRU 102a, bounce off the obstacle 202, and be received by the bistatic receiving WTRU 102b in the single bounce path. The expected bistatic RTT may be computed as (d_t + d_r /c, where d_t and d_r are the distances between the transmitting WTRU 102a and the obstacle 202 and the receiving WTRU 102b and the obstacle 202, respectively, as in FIG. 7.

[0252] In one example, the expected bistatic RTT may be expressed in terms of seconds, number of symbols, number of slots, number of frames, and/or number of subframes.

[0253] In another example, the WTRU may also determine the uncertainties associated with the expected monostatic and bistatic RTTs. The WTRU, in one example, may be configured to report at least one of the following uncertainty sources:

• Uncertainty associated with the obstacle location, o For example, the obstacle location uncertainty may be associated with the measurement error (e.g., RTT, AoA), the WTRU Tx or Rx timing error, clock synchronization error between Tx, Rx), resolution error (e.g., time resolution, angle resolution), and/or

• Uncertainty associated with the transmitting/receiving WTRU locations, o For example, the Tx/Rx WTRU location errors may be associated with the location estimation measurement errors, Tx/Rx timing error, clock synchronization error, error in reference locations (e.g., TRP location error)

[0254] In certain representative embodiments, an indication may be provided to WTRUs in the vicinity about the presence/emergence of obstacles in the vicinity.

[0255] In certain representative embodiments, procedures may be performed to determine the sensing RS configurations for the WTRUs/TRPs for resource allocation. [0256] In certain representative embodiments, a WTRU(s) may perform resource efficient obstacle detection in an environment with multiple WTRUs which provides benefits such as early warning (e.g., for autonomous driving), blockage prediction

[0257] In certain representative embodiments, a WTRU(s) may perform improved and efficient continuity of sensing of an obstacle between the WTRUs for obstacle tracking.

[0258] In certain representative embodiments, a WTRU(s) may perform improved accuracy and precision of sensing.

[0259] Anchor WTRU Selection for Bistatic Sensing

[0260] RS Configurations for Sensing

[0261] SL-PRS configuration

[0262] In certain representative embodiments, a WTRU (e.g., target WTRU) may be (pre)configured with one or more SL-PRS configurations.

[0263] In one example, a target WTRU may send the request to the network (e.g., LMF, gNB, another WTRU, entity that configures reference signals to the WTRU) for SL-PRS configuration for sensing, such as in any uplink physical channels (e.g., PUSCH or PUCCH), via higher layer signaling (e.g., MAC-CE or RRC, SLPP), and/or via LPP messages.

[0264] In one example, the target WTRU may receive the one or more sets of SL-PRS configuration(s) from the network (e.g., LMF, gNB) including (e.g., at least) any of the time, frequency, periodicity, and/or spatial configurations. In one example, in the case of multiple configuration sets, a target WTRU may also receive an index (e.g., SL-PRS configuration ID) associated with each configuration.

[0265] PRS/SRSp Resource Configuration

[0266] In certain representative embodiments, a WTRU(s) may be (pre)configured with one or more DL- PRS configurations.

[0267] In one example, a (e.g., target) WTRU may (e.g., also) receive a set of (pre)configured DL-PRS configuration parameters for obstacle location estimation from the network. The (pre)configuration may include configurations corresponding to one or more TRPs. Each configuration may be associated with a TRP index (e.g., TRP ID) and a configuration index (e.g., configuration ID).

[0268] In one example, (e.g., a subset of) (pre)configuration(s) may also be associated with on-demand bistatic sensing requesting on behalf of the network. These on-demand (pre)configurations may be transmitted by the network in the event of an on-demand request.

[0269] In one example, the WTRU may also receive assistance information from the network consisting of (e.g., at least) any of the following:

• DL-PRS configuration I D(s) which may be associated with the DL-PRS configuration;

• TRP validity time: o The validity time indicates the time instances where each TRP may be available and may be characterized by at least one of the following parameters:

■ TRP ID and/or TRP locations,

■ Start or end time(s) of the availability (e.g., in terms of symbol indices, slot indices, frame indices, absolute time, relative time with respect to a reference point), and/or

■ Duration of the availability (e.g., in terms of number of symbols, slots, frames, subframes, seconds);

• Geographical coordinates of the TRPs; and/or

• Trigger conditions for if configured with on-demand DL-PRS resources

[0270] In certain representative embodiments, a WTRU(s) may be (pre)configured with one or more sets of SRSp configurations.

[0271] In an example, a target WTRU may receive one or more sets of SRSp configurations from the network for obstacle sensing.

[0272] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may receive QoS configurations for sensing.

[0273] In one example, any SL-PRS/DL-PRS/SRSp configurations may also include or be associated with a QoS requirement for a location. A QoS requirement may include (e.g., at least) any of the following parameters:

• The sensing accuracy requirements: o For example, the target WTRU may be (pre)configured with the accuracy requirement in terms of distance in meters (e.g., horizontal accuracy, vertical accuracy), in time in seconds (e.g., timing accuracy associated with the configured sensing method), in angle in degrees, radians (e.g., angle accuracy associated with the configured angle-based sensing method);

• The sensing latency requirements: o For example, the target WTRU may be (pre)configured with the latency requirements in terms of seconds. The WTRU may be configured with a total sensing duration which may also be associated with the latency requirements; and/or

• The sensing reliability requirements: o For example, the target WTRU may be (pre)configured with the reliability requirements which may be associated with the reliability in sensing measurements measured in variance (e.g., seconds² if the configured sensing method is time based, degrees² if the configured sensing method is angle based), reporting reliability which may be expressed in terms of seconds (e.g., time delay between measurement and reporting) [0274] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may transmit its sensing capability information.

[0275] In one example, a WTRU may be configured and/or a WTRU may receive a request from the network to transmit its capability information and/or assistance information to the network. Capability and/or assistance information may include (e.g., at least) any of the following:

• The target WTRU location, and/or the associated uncertainty range;

• Transmission capabilities: o For example, the target WTRU may indicate the maximum sensing range associated with its maximum transmission power. If the transmission power is N dBm, the maximum sensing range is X meters based on the configured association rules; and/or o In one example, the WTRU may indicate transmission power based on the SL-PRS configuration, the configured downlink pathloss RS, or transmission power used for data communication (e.g., transmission power determined for PUSCH, PUCCH, SRSp, SRS);

• Sensing measurement capabilities: o For example, the target WTRU may indicate whether it may be capable of transmitting and/or measuring the positioning RS (e.g., SL-PRS, DL-PRS, SRSp) resources; o For example, the target WTRU may indicate the measurement it supports (e.g., ToA, RTT, RSTD, AoD, AoA, doppler shift); o For example, the target WTRU may indicate its maximum time (e.g., Y ns) and/or frequency resolution (e.g., Z Hz) associated with the time and frequency measurements,

■ For example, the maximum time resolution may depend on the total available bandwidth for sensing. The maximum time resolution may hence depend on the ability of the WTRU to process (e.g., compute FFT) large frequency domain samples and hence the available energy and computation resources. Additionally, depending on its capability, the WTRU may also have an improved sensing time resolution based on its ability to oversample the received SRSp resources, and/or

■ For example, the maximum doppler resolution may depend on the number of OFDM symbols transmitted/measured in each measurement occasion; o For example, the target WTRU may indicate the sensing method that it supports (e.g., RTT); o For example, the target WTRU may indicate whether it can compute and/or estimate the obstacle location (e.g., coordinates) corresponding to the measurements; o For example, the target WTRU may indicate whether it can compute and/or estimate the obstacle velocity from the measurements; o For example, the target WTRU may indicate whether it requires another assisting entity (e.g., anchor WTRU, server WTRU, TRP ) for calculating the final location coordinates of the obstacles; and/or o For example, the target WTRU may indicate how may obstacle it may be capable of measuring and estimating the location of; and/or

• Sensing reporting capabilities: o For example, the target WTRU may indicate whether the final location estimate may be absolute or relative to its location; o For example, the target WTRU may indicate the frequency with which it may report the measurements/estimations; and/or o For example, the target WTRU may indicate how many measurements and/or estimations it can report.

[0276] In another example, a WTRU may transmit capability information to the network uninitiated without an indication from the network due to (e.g., at least) any of the following conditions:

• The target WTRU determines that the capability information may be useful for the network to assess the requirement for anchor WTRUs/TRP and assist it in anchor WTRU selection;

• The target WTRU determines that the measurement capability may assist the network in determining the sensing methods (e.g., RTT);

• The target WTRU determines the reporting capabilities (e.g., total number of obstacle) may assist the network in assigning the WTRU to perform appropriate tasks (e.g., count the number of obstacles); and/or

• The target WTRU determines the maximum sensing range and the sensing time/doppler resolution information can assist the network in allocating the sensing configurations (e.g., SRSp resources) for the WTRU.

[0277] Bistatic RTT thresholds

[0278] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may receive bistatic RTT threshold information from the network.

[0279] FIG. 8 is a system diagram illustrating an example of bistatic RTT thresholds and a sensing coverage area.

[0280] In one example, a WTRU may be configured with the bistatic RTT thresholds (e.g., threshold_min and thresholdjnax) by the network that are associated with (e.g., define) the bistatic sensing coverage area 802 (e.g., ellipse) between the two entities (e.g., target WTRUs, anchor WTRUs, TRPs), such as WTRUs 102a and 102b, in bistatic sensing as shown in FIG. 8. In one example, each of the thresholds may be associated (e.g., unique) to each bistatic sensing pair(s). The WTRU may receive a minimum threshold 804, referred to in this disclosure as “thresholdjnin”, and a maximum threshold 806, referred to in this disclosure as “thresholdjnax”.

[0281] In one example, the sensing coverage area (e.g., the ellipse) may also be alternatively represented by a major axis and the minor axis with the entity locations as the two foci. In another example, the threshold_min and thresholdjnax may also be replaced by major and the minor axis distance thresholds as shown in FIG. 8. For example, the alternative representation for threshold nax may be the major axis threshold (e.g., max_1) and minor axis threshold (e.g., max_2).

[0282] In another example, the bistatic sensing coverage area (e.g., the ellipse) may also alternatively be represented by the combination of angle pairs between a point in the circumference of the ellipse, an entity location (e.g., WTRU1), and another entity location (e.g. WTRU2). This is shown in

and 0₂.

[0283] In one example, since the thresholdjnax and threshold_min between two entities may be dependent on different capabilities of each entity, they may also depend on the transmitting entity. For example, in case of gNB-UE bistatic sensing, the DL thresholdjnax may be different from UL thresholdjnax. [0284] In one example, the WTRU (e.g., target WTRU(s), anchor WTRU(s), server WTRU(s)) may receive information indicating threshold_min and thresholdjnax from the network. The WTRU may receive these thresholds via downlink physical channel (e.g., PDSCH, PDCCH) and/or via higher layer signalling (e.g., UCI, MAC-CE, RRC, and/or LPP message).

[0285] In another example, the WTRU may also receive the thresholds from another WTRU (e.g., target WTRU(s), anchor WTRU(s), server WTRU(s)). The WTRU may receive these thresholds via the sidelink physical channel (e.g., PSSCH, PSCCH) and/or via lower and higher layer signalling (e.g., SCI, SL-MAC- CE, PC5-RRC message), such as independently or as a part of the SL-PRS configuration.

[0286] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may autonomously determine the bistatic RTT thresholds.

[0287] In one example, a target WTRU may be configured by the network to determine the bistatic RTT thresholds autonomously.

[0288] For example, a target WTRU may determine thresholdjnax based on (e.g., at least) any of the following:

• Maximum transmission power: o The target WTRU may compute and/or estimate the maximum thresholdjnax based on the maximum transmission power of the transmitting TRP/UE. This may correspond to the maximum RTT (or correspondingly distance) between the transmitter, obstacle and the receiver such the received SNR/RSRP/signal quality may be above a (pre)configured threshold to locate the obstacle. For example, a transmit power of X dB may be associated with the thresholdjnax of Y ms, o For example, the WTRU may compute and/or estimate Y 1 ms thresholdjnax if its maximum transmit power above a (pre)configured threshold and Y2 ms otherwise. In one example, Y1 may be greater than Y2;

• QoS requirement: o The WTRU may compute and/or estimate the thresholdjnax based on the (pre)configured QoS requirement of the obstacle location (e.g., horizontal location accuracy, vertical location accuracy, reliability ). For example, X m horizontal accuracy, Y m vertical accuracy may be associated with threshold nax of Z ms, o For example, the WTRU may compute and/or estimate Y1 ms thresholdjnax if its QoS requirement (e.g., accuracy) is below a (pre)configured threshold and Y2 ms otherwise. In one example, Y1 may be greater than Y2;

• Obstacle velocity: o For example, X m/s velocity may correspond to thresholdjnax of Y ms, o For example, the WTRU may compute and/or estimate Y1 ms thresholdjnax if the obstacle’s velocity is below a (pre)configured threshold and Y2 ms otherwise. In one e.g., Y1 may be greater than Y2, o The target WTRU may estimate a small threshold for above threshold obstacle velocity to confine the selection of anchor WTRU(s)/TRP(s) to the ones closer to the obstacle such that the target WTRU and the anchor WTRU may continue to sense the obstacle despite its high velocity;

• Uncertainty in locations/velocity of the entities (e.g., WTRUs): o The WTRU may compute and/or estimate the thresholdjnax based on the uncertainty in the locations and/or velocities of the entities (e.g., transmitting WTRUs/TRPs, receiving WTRU/TRPs), o The WTRU may compute and/or estimate a thresholdjnax Y1 ms if the uncertainty in the WTRU location is above a (pre)configured threshold and Y2 ms otherwise. For example, Y1 may be less than Y2, o For example, the uncertainty in the entity locations may cause error in obstacle location and/or velocity as well. Hence the WTRU may choose a small thresholdjnax to limit the obstacle error due to the uncertainty, o For example, X1 m horizontal and Y1 m vertical uncertainty may be associated with a Z1 ms thresholdjnax, o For example, X2 m/s uncertainty in the entity’s velocity may be associated with a Z2 ms thresholdjnax; • Distance between the entities (e.g., target WTRU, anchor WTRU, TRP): o The WTRU may compute and/or estimate a thresholdjnax Y1 ms if the distance between the target WTRU and the anchor WTRU/TRP is above a (pre)configured threshold and Y2 ms otherwise. In one example, Y1 may be greater than Y2, o For example, a X m distance between the entities may correspond to a Y ms thresholdjnax; and/or

• Total number of available anchor WTRU(s)/TRP(s): o The WTRU may compute and/or estimate a threshold nax Y1 ms if the total number of available (e.g., discovered) anchor WTRU(s)/TRP(s) is above a (pre)configured threshold and Y2 ms otherwise, o As for a positioning method, we require a limited number of anchor WTRUs, having a low threshold may limit the total number of suitable anchor WTRUs for bistatic sensing.

[0289] In one example, a target WTRU may determine threshold_min based the following:

• Effective bandwidth: o The WTRU may determine threshold_min Y1 ms if the effective bandwidth is below a (pre)configured threshold and Y2 ms otherwise. For example, Y1 may be greater than Y2, o The effective bandwidth is associated with the ambiguity zone where the receiving WTRU may not be able to differentiate between the LoS path and the single bounce path from the obstacle, o For example, the WTRU may associate X Hz of effective bandwidth with Y ms of thresholdjnin.

[0290] In another example, the WTRU may also be configured with a set of thresholdjnax and threshold_min bistatic thresholds (e.g., via table and/or equation(s)), such as which may be dependent on various values of the above-mentioned parameters. The WTRU may then, based on the determined value of the parameter, select a suitable thresholdjnin and thresholdjnax from the (pre)configured set.

[0291] Anchor WTRU selection for SL bistatic sensing

[0292] Anchor WTRU discovery procedure

[0293] In certain representative embodiments, a WTRU(s) may determine to initiate a discovery procedure.

[0294] In one example, a target WTRU may initiate a discovery procedure to find other (e.g., anchor) WTRU(s) who may sense or assist in sensing an obstacle.

[0295] In one example, a discovery procedure may be initiated by a target WTRU based on obstacle detection. The discovery procedure may be triggered by (e.g., at least) any of the following conditions: • The target WTRU determines the conditions concerning the WTRU’s detection of an obstacle (e.g., decrease in communication performance above a (pre)configured threshold, decrease in the positioning performance below a (pre)configured threshold);

• The distance between the target WTRU and the obstacle location is below a (pre)configured threshold;

• The velocity of the located obstacle is above a (pre)configured threshold;

• The determined uncertainty in the obstacle location is above a (pre)configured threshold; and/or

• The indicated priority of the obstacle above a (pre)configured threshold

[0296] In another example, a target WTRU may be indicated by the network to initiate a discovery procedure.

[0297] In certain representative embodiments, a WTRU(s) may broadcast a discovery message.

[0298] In one example, a target WTRU may broadcast a discovery message to the other WTRU(s) in its vicinity, such as via either PC5 interface or any other interface (e.g., RRC) allowing connection between the WTRUs.

[0299] In one example, a discovery message may include information indicating (e.g., at least) any of the target WTRU, the obstacle’s information, and/or the requirements and/or capabilities for the discovered WTRU’s to be a potential anchor WTRU.

[0300] In one example, a WTRU may transmit (e.g., at least) any of the following in a discovery message:

• Target WTRU information: o Target WTRU ID (e.g., RNTI), or any other IDs that are used to identify the target WTRU, o Target WTRU location and/or the associated uncertainty range, o Target WTRU coverage information (e.g., in coverage, cell ID), o Target WTRU sensing zone (e.g., maximum monostatic RTT threshold), o (Maximum) transmission power, o Synchronization source information (e.g., time/frequency/phase synchronization), o Supported frequency range (e.g., FR1, FR2) and/or sub-carrier spacing and/or (maximum) bandwidth for SL-PRS;

• Obstacle information: o Obstacle location and/or uncertainty range, o Obstacle velocity and/or uncertainty range, o QoS requirement for obstacle location (e.g., accuracy, latency, reliability requirements), and/or o How the obstacle location is determined (e.g., by network, by monostatic sensing); and/or

• Required anchor WTRU capabilities: o Capability to estimate its location, o Capability to perform sidelink measurements (e.g., time, angle, frequency, frequency shift), o Capability to perform a specific positioning method (e.g., RTT), o Capability to obtain location coordinates from the measurements, o Capability to report its location to the network, WTRU (e.g., server WTRU), o Capability to report the obstacle(s)’ location to the network, WTRU (e.g., server WTRU), o Capability to report the measurements to the network, WTRU (e.g., server WTRU) o Sensing window configurations (e.g., start time, duration, stop time), o Required time resolution threshold for time related positioning methods (e.g., RTT, TDoA) threshold, o Required angle resolution threshold for angle related positioning methods (e.g., AoD, AoA), o Required velocity resolution threshold for velocity related positioning methods, and/or o Required minimum energy threshold,

[0301] In another example, a WTRU may request the network to provide a list of WTRUs in the vicinity.

[0302] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may receive a discovery response including assistance information.

[0303] In certain representative embodiments, a target WTRU may (e.g., also) request assistance information to be sent by the discovered anchor WTRU(s) upon discovery in their response (e.g., in a semistatic or dynamic message).

[0304] In one example, the target WTRU may receive a response to a discovery message upon determining its suitability for sensing based on the information and capability requirements from the anchor WTRU(s).

[0305] In one example, a target WTRU may receive a set of assistance information including (e.g., at least) any of the following:

• Anchor WTRU information: o Anchor WTRU ID (e.g., RNTI), or any other IDs that are used to identify the anchor WTRU, o Anchor WTRU location and/or its uncertainty range, o Anchor WTRU velocity and/or its uncertainty range, o Anchor WTRU coverage information (e.g., in coverage, out of coverage, cell ID), and/or o Anchor WTRU duplexing information (e.g., full duplex WTRU); and/or

• Anchor WTRU capability information: o (Maximum) transmit power, o Supported sensing methods (e.g., RTT), o Supported measurements (e.g., ToA, RSTD, AoA), o Supported maximum number of obstacles, o Available sensing start time and duration, and/or o Available WTRU energy

[0306] In another example, a target WTRU may also request and receive the potential anchor WTRU(s) information including their state, capabilities and/or assistance information from the network.

[0307] Anchor WTRU Selection and Request for Bistatic Sensing

[0308] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may determine the anchor WTRU(s) that may assist in bistatic sensing with the help of the obstacle state and/or the assistance information from the potential anchor WTRU(s).

[0309] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may select the anchor WTRU(s) for bistatic sensing.

[0310] In one example, a target WTRU may determine the set of anchor WTRU(s) that may assist itself in bistatic sensing from the set of the discovered anchor WTRU(s) that responded to the discovery message. The WTRU may select the set of anchor WTRU(s) based on the received assistance information and/or the bistatic RTT thresholds (e.g., threshold_min, thresholdjnax).

[0311] FIG. 9 is a system diagram illustrating another example of an expected bistatic RTT.

[0312] FIG. 10 is a system diagram illustrating an example of anchor WTRU selection based on threshold information (e.g., thresholdjnax)

[0313] In one example, a WTRU 102 may select the anchor WTRU(s) based on the anchor WTRU(s) satisfying (e.g., at least) any of the following conditions:

• The expected bistatic RTT (e.g., determined based on at least the location of the target WTRU 902, anchor WTRU 904, and obstacle 202 location, as in FIG. 9) associated with the target WTRU 902 and the anchor WTRU 904 is below the (pre)configured threshold nax; o For example, this condition ensures that the detected obstacle is within the sensing coverage area 800 determined by thresholdjnax and hence the target and the anchor WTRUs may be able to perform bistatic sensing while ensuring the QoS requirements, and/or o For example, as in FIG. 10, since the obstacle is not in the coverage area 800b determined by thresholdjnax of Anchor WTRU2 1002, the anchor WTRU2 1002 is not selected for bistatic sensing;

• The expected bistatic RTT associated with the target WTRU 902 and the anchor WTRU 904 is above the (pre)configured threshold jnin: o For example, this condition ensures that the anchor WTRUs are able to distinguish between the LoS path and the single bounce path from the obstacle 202 allowing for accurate location of the obstacle 202;

• The distance between the anchor WTRU and the obstacle 202 is below a (pre)configured threshold;

• The uncertainty in the anchor WTRU location and/or velocity is below a (pre)configured threshold, o For example, as the obstacle location estimation is dependent on the accuracy of the locations of the target and anchor WTRUs, the threshold on uncertainty may allow for accurate location of the obstacle;

• The velocity of the anchor WTRU is below a (pre)configured threshold, o For example, if the anchor WTRU is mobile and has a velocity above a (pre)configured threshold, the target WTRU would need to assess the suitability of the anchor WTRU every measurement occasion due to the changing expected bistatic RTT and its uncertainty, o For example, this may require the anchor WTRU to frequently (e.g., periodically) transmit its state (e.g., location and/or velocity) and the associated uncertainty, and/or o This may reduce the sensing performance and increase signalling and computation complexities;

• The relative velocity of the anchor WTRU(s) with the target WTRU is below a (pre)configured threshold, o For example, if the target WTRU is a moving vehicle and discovers another vehicle with the velocity difference below the (pre)configured threshold, the WTRU may select the anchor WTRU to assist it in bistatic sensing;

• The anchor WTRU(s) have the known/same time/frequency/phase synchronization source, o For example, certain positioning methods require time/frequency/phase synchronization (e.g., RTT, carrier phase positioning). The target WTRU may select the anchor WTRU(s) if they are (i) synchronized to the same entity (e.g., TRP), and/or (ii) synchronized to the entity with a known synchronization offset in between;

• The anchor WTRU(s)’ sensing duration is above a (pre)configured threshold; and/or

• The anchor WTRU(s)’ available sensing energy is above a (pre)configured threshold.

[0314] In one example, a target WTRU may be configured or may determine (e.g., select) at least N anchor WTRU(s) from the set of discovered anchor WTRU(s), where the value of N may be configured by the network and/or peer WTRU (e.g., WTRU with LMF capability, server WTRU). The WTRU may determine a (e.g., large) total number of anchor WTRU(s) for bistatic sensing based on (e.g., at least) any of the following: • The number of WTRUs required in the configured positioning method is above a (pre)configured threshold,

• The uncertainty in obstacle location and/or velocity is above a (pre)configured threshold,

• The uncertainty in target WTRU location and/or velocity is above a (pre)configured threshold,

• The obstacle velocity is above a (pre)configured threshold, and/or

• The QoS requirement (e.g., accuracy, reliability, latency ) is above a (pre)configured threshold.

[0315] In one example, if the selected anchor WTRUs is less than the (pre)configured threshold (e.g., W), the target WTRU may:

• Increase the number of anchor WTRU(s) by reducing the restrictions for the anchor WTRU selection criteria by changing the values of the thresholds, o For example, the WTRU may reduce the lower bound thresholds (e.g., criteria with the values below a (pre)configured thresholds) and/or increase the upper bound thresholds (e.g., criteria with the above a (pre)configured thresholds); or

• Terminate the sensing procedure.

[0316] In one example, if the total number of selected anchor WTRU(s) is more than a (pre)configured threshold (e.g., W), the WTRU may down select (e.g., reduce) the selected anchor WTRUs based on prioritization of one or more of selection conditions. For example, the WTRU may select (e.g., W) anchor WTRUs with the least expected bistatic RTT.

[0317] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may send a bistatic sensing request to the anchor WTRUs.

[0318] In one example, a target WTRU may send a request to the anchor WTRU(s) for bistatic sensing through (e.g., at least) any of the sidelink-specific signals (e.g., SCI, SL-MAC-CE, and/or PC5-RRC messages). The target WTRU may either send the request as a groupcast or unicast transmission to the selected anchor WTRU(s).

[0319] In one example, a target WTRU request may include an indication of the amount resources that may be transmitted. In one example, the target WTRU may indicate the resources required for transmission and/or reception of SL-PRS by at least one of the following:

• Sensing window configurations o Start or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point), o Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds), o For example, the sensing window may indicate the time that the anchor WTRU(s) may need to reserve for sensing; • Target WTRU’s QoS requirement for obstacle location (e.g., accuracy, latency, reliability);

• SL-PRS transmission bandwidth (e.g., in terms of RBs, Hz);

• The target WTRU’s total energy for sensing (e.g., in terms of joules); and/or

• Transmission power level (e.g., indication of pathloss RS for determination of power, relative difference in power with respect to a pathloss RS or transmission power).

[0320] This assistance information may explicitly or implicitly indicate to the target WTRUs of the amount of resources that the target WTRU may reserve and transmit for bistatic sensing. This may allow the anchor WTRU(s) to make a decision regarding whether to participate in assisting the target WTRU or not.

[0321] SL-PRS Configuration

[0322] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may receive an indication from one or more than one anchor WTRU(s) agreeing for bistatic sensing (e.g., “Yes”, ACK). The WTRU may determine to configure the SL-PRS resources for bistatic sensing, such as where the total number of anchor WTRUs who responded ‘Yes” to the bistatic sensing is above a (pre)configured threshold.

[0323] In certain representative embodiments, a WTRU(s) (e.g., target WTRU) may determine a SL-PRS configuration.

[0324] In one example, a target WTRU may determine a SL-PRS transmission configuration based on the detected obstacle location and/or and the selected anchor WTRU(s).

[0325] In one example, a target WTRU may determine a SL-PRS time configuration with a number of symbols (e.g., 2 symbols per resource, 12 symbols per resource ).

[0326] In one example, a target WTRU may determine a SL-PRS time configuration with N1 number of OFDM symbols per resource based on (e.g., at least) any of the following conditions:

■ The distance between the target WTRU and the obstacle is below a (pre)configured threshold,

■ The bistatic RTT thresholdjnax is below a (pre)configured threshold,

■ The bistatic RTT threshold_min is above a (pre)configured threshold,

■ The expected bistatic RTT is below a (pre)configured threshold,

■ The QoS accuracy requirement for time-based location estimation is above a (pre)configured threshold,

■ The QoS latency requirement is above a (pre)configured threshold,

■ The energy available of the target WTRU is above a (pre)configured threshold,

■ The sensing duration available to the anchor WTRUs is below a (pre)configured threshold,

■ The velocity of the obstacle is above a (pre)configured threshold,

■ The number of selected anchor WTRUs is below a (pre)configured threshold, and/or The obstacle priority to the target WTRU is above a (pre)configured threshold; and/or o The WTRU may select the configuration N2 number of OFDM symbols otherwise. In one example, N1 may be greater than N2.

[0327] In one example, a target WTRU may determine a SL-PRS frequency configuration with (e.g., at least) any of a varying allocated bandwidth (e.g., 100 RBs, 60 RBs) and/or comb shape (e.g., comb 2, comb 12).

[0328] In one example, a target WTRU may determine a SL-PRS frequency configuration (e.g., with a bandwidth allocation of M1 (e.g., 100 MHz) and/or Comb-N1 based on (e.g., at least) any of:

■ The thresholdjnax is below a (pre)configured threshold,

■ The thresholdjnin is below a (pre)configured threshold,

■ The expected bistatic RTT is below a (pre)configured threshold,

■ The QoS latency requirement is above a (pre)configured threshold,

■ The velocity of the obstacle is above a (pre)configured threshold,

■ The number of the selected anchor WTRUs is below a (pre)configured threshold, and/or

■ The obstacle priority to the target WTRU is above a (pre)configured threshold [0329] In one example, a target WTRU may determine a SL-PRS time configuration with another set of frequency characteristics, such as with a bandwidth allocation of M2 (e.g., 50 MHz) and/or Comb-N2 otherwise.

[0330] In one example, a target WTRU may determine a SL-PRS type configuration (e.g., periodic, aperiodic, semi-persistent) based on (e.g., at least) any of the following:

■ the QoS requirement (e.g., accuracy, reliability) is above a (pre)configured threshold,

■ the total available sensing duration is above a (pre)configured threshold,

■ the obstacle velocity is above a (pre)configured threshold,

■ the uncertainty in obstacle velocity is above a (pre)configured threshold, ■ the target WTRU and/or the anchor WTRU velocity is above a (pre)configured threshold, and/or

■ the uncertainty in the target WTRU and/or the anchor WTRU velocity is above a (pre)configured threshold

[0331] For example, the target WTRU may select/determine an aperiodic configuration if (e.g., at least) any of the following are satisfied:

■ the total available sensing duration is below a (pre)configured threshold,

■ the obstacle velocity is below a (pre)configured threshold,

■ the uncertainty in obstacle velocity is below a (pre)configured threshold,

■ the target WTRU and/or the anchor WTRU velocity is below a (pre)configured threshold, and/or

■ the uncertainty in the WTRU and/or the target WTRU velocity is below a (pre)configured threshold

[0332] For example, the target WTRU may select/determine a semi persistent configuration if (e.g., at least) any of the following are satisfied:

■ the QoS requirement (e.g., accuracy, reliability) is below a (pre)configured threshold,

■ the total available sensing duration is below a (pre)configured threshold,

■ the obstacle velocity is above a (pre)configured threshold,

■ the uncertainty in obstacle velocity is above a (pre)configured threshold,

■ the target WTRU and/or the anchor WTRU velocity is above a (pre)configured threshold, and/or

■ the uncertainty in the target WTRU and/or the anchor WTRU velocity is above a (pre)configured threshold.

[0333] In one example, a target WTRU may determine a SL-PRS periodicity configuration (e.g., in cases of periodic or semi-persistent configurations) having a (e.g., different) SL-PRS resource periodicity (e.g., 1 slot, 5 slots).

[0334] In one example, a target WTRU may determine a SL-PRS periodicity configuration with a periodicity P1 based on (e.g., at least) any of the following conditions:

■ The thresholdjnax is below a (pre)configured threshold,

■ The velocity of the obstacle is above a (pre)configured threshold,

■ The sensing duration allocated is below a (pre)configured threshold, ■ The QoS latency requirement is above a (pre)configured threshold,

■ The available sensing energy is above a (pre)configured threshold, and/or

■ The obstacle priority to the target WTRU is above a (pre)configured threshold

[0335] In one example, a target WTRU may determine a SL-PRS periodicity configuration with a periodicity P2 otherwise.

[0336] In one example, a target WTRU may determine a SL-PRS spatial configuration (e.g., AoDs, beamwidth, spatial coverage of the SL-PRS resources) with a spatial relationship between SL-PRS and other (e.g., SL) RSs.

[0337] FIG. 11 is a system diagram illustrating spatial SL-PRS configurations based on threshold information (e.g., thresholdjnax and threshold_min)

[0338] For example, the WTRU may select/determine to prioritize the SL-PRS resources such that the AoD of the selected SL-PRS resources are within the coverage area 800a created by thresholdjnax and threshold_min, as illustrated in FIG. 11.

[0339] For example, the WTRU may select/determine to prioritize the SL-PRS resources such that the difference in AoD of the selected SL-PRS resources and expected AoD to the obstacle are below a (pre)configured threshold. For example, the WTRU may determine to prioritize the SL-PRS resources with X1 degrees beamwidth based on (e.g., at least) any of the following conditions:

■ the distance between the target WTRU and the obstacle is below (pre)configured threshold,

■ the uncertainty in the obstacle location is above a (pre)configured threshold, and/or

■ the uncertainty in target WTRU location is above a (pre)configured threshold.

[0340] For example, the WTRU may determine to prioritize the SL-PRS resources such that a X2 degrees beamwidth is selected otherwise.

[0341] For example, the WTRU may select/determine a (sub)set of SL-PRS resources such that a coverage angle is 01 degrees (e.g., 60 degrees) based on (e.g., at least) any of the following conditions:

■ the expected bistatic RTT is below a (pre)configured threshold,

■ the uncertainty in obstacle location is above a (pre)configured threshold, and/or

■ the uncertainty in WTRU location is above a (pre)configured threshold.

[0342] For example, the WTRU may select/determine a (sub)set of SL-PRS resources such that a coverage angle 02 (e.g., 15 degrees) is selected otherwise.

[0343] In one example, the WTRU may determine spatial configurations of SL-PRS based on thresholdjnax and threshold_min as illustrated in FIG. 11. For example, the WTRU may determine to use SL-PRS or other SL RSs (e.g., CSI-RS) whose AoD is within thresholdjnin and thresholdjnax. The WTRU may indicate to anchor WTRUs which SL-PRS configurations to use (e.g., via SL-PRS configuration ID), or by indicating RS ID (e.g., SL-CSI-RS ID) along which SL-PRS will be transmitted from the target WTRU. In another example, the WTRU may indicate expected AoD or AoA, associated with a SL-PRS resource (e.g., index) to the anchor WTRU to inform which direction the SL-PRS is transmitted or received, respectively.

[0344] In another example, the target WTRU may be configured with more than one set of SL-PRS configurations by the network or a peer WTRU (e.g., server WTRU), where each of the SL-PRS configuration may be identified by a configuration ID. Each of the SL-PRS configurations may contain different time, frequency, and/or periodicity configurations. The target WTRU may choose a SL-PRS configuration based on the conditions stated in the configuration determination by the target WTRU. In one example, the configured SL-PRS resources may either partially or totally correspond to the indicated configuration ID. In one example, the SL-PRS configuration may also correspond to one or more configurations indices.

[0345] In another example, the target WTRU may be (pre)configured with one or more sets of resource pools, where each resource pool may contain one or more SL-PRS configurations. The WTRU may select the configurations from the resource pool based on the conditions stated in the configuration determination by the target WTRU. In one example, the selected resource pool may be identified by an index.

[0346] In certain representative embodiments, a WTRU may perform a fallback operation, such as when a request rejection is received.

[0347] In another example, if the total number of positively responding WTRU’s for bistatic sensing is below a threshold, the target WTRU may determine to perform/continue to perform monostatic sensing, or the target WTRU may determine to terminate the sensing procedure.

[0348] In certain representative embodiments, a (e.g., target) WTRU may indicate the selected SL-PRS resources to the anchor WTRU(s).

[0349] In one example, a target WTRU may indicate at least some parameters of the configuration to the anchor WTRU(s). The target WTRU may use a semi-static message (e.g., SCI, SL-RRC) to transmit (e.g., at least) any of the following parameters:

• Measurement time window such as (e.g., at least) any of: o Start or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point), o Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds), o Periodicity of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds), o The target WTRU may determine the measurement time window configurations based on the SL-PRS configurations;

• Assisting measurement information that may assist the anchor WTRU: o For example, the target WTRU may indicate the SL-PRS resource I D(s), SL-PRS resource set I D(s) that may be likely to be reflected from the obstacle, o For example, the target WTRU may indicate any combination of the number of symbols/slots, bandwidth, comb values, periodicity , o For example, the target WTRU may indicate the expected RTT range (e.g., in terms of symbol indices, slot indices, frame indices, absolute time, relative time with respect to a reference point (e.g., start time of measurement window)) when it may receive reflected from the obstacle, o For example, the target WTRU may indicate the expected AoA range (e.g., with respect to a absolute orientation (e.g., geographical north), target WTRU orientation, anchor WTRU orientation) relevant to the obstacle’s (coarse) location, o For example, the target WTRU may indicate the type of transmission (e.g., periodic, semi- persistent, aperiodic) and may also indicate the periodicity of the transmission (if relevant), and/or o For example, the target WTRU may indicate the LoS/NLoS ID between the target and the anchor WTRU; and/or

• Assisting reporting information such as (e.g., at least) any of: o For example, the target WTRU may indicate the reporting time (e.g., in terms of symbol indices, slot indices, frame indices, absolute time, relative time with respect to a reference point (e.g., end of measurement window)), o For example, the target WTRU may indicate the reporting frequency (e.g., periodic) and/or its periodicity along with the reporting trigger, o For example, the target WTRU may indicate the priority associated with reporting the measurements and/or estimations.

[0350] In another example, if the target WTRU was configured with one or more sets of configurations by the network, the WTRU may indicate a configuration index (e.g., configuration ID) to the anchor WTRU(s).

[0351] In another example, if the target WTRU determined the SL-PRS configurations from the configured resource pool, the target WTRU may indicate the resource pool index (e.g., resource pool ID) to the anchor WTRU(s).

[0352] In another example, the target WTRU may (e.g., implicitly) indicate the SL-PRS configurations based on (e.g., at least) any of the following: Thresholdjnax: o The target WTRU may indicate the configured SL-PRS resources (e.g., SL-PRS resource ID(s), SL-PRS resource set ID(s), SL-PRS AoD(s), beamwidth of the resource sets ) to the anchor WTRU(s) based on the bistatic sensing coverage area defined by thresholdjnax. o For example, the target WTRU may indicate to the anchor WTRU(s) at least one of the following configurations with an above (pre)configure threshold nax:

■ SL-PRS resource I D(s) with N number of (unique) beams,

■ SL-PRS resource set with X MHz bandwidth,

■ Y dBm transmission power, and/or

■ Z ms sensing duration o For example, the target WTRU may indicate another set of configurations otherwise;

• Threshold jnin: o For example, the target WTRU may indicate to the anchor WTRU(s) a bandwidth (e.g., X1 MHz) if threshold_min is below a (pre)configured threshold;

• Expected bistatic RTT: o For example, the target WTRU may indicate to the anchor WTRU(s) the SL-PRS time resources configurations (e.g., N OFDM symbols, Z ms sensing duration) and/or frequency resources (e.g., Comb-M, X MHz bandwidth) if the expected bistatic RTT is above a (pre)configured threshold, o The WTRU may indicate another set of time and/or frequency configurations otherwise;

• One or more combinations of SL-PRS periodicity, bandwidth, sensing duration, time offset, comb patterns: o For example, the target WTRU may indicate the SL-PRS configurations based on one or more of the above indicated parameters; and/or o For example, the target WTRU may indicate the SL-PRS configurations to the anchor WTRU(s) from the (pre)configured set such that the difference between one or more of the indicated parameters with the (pre)configured parameters is below a (pre)configured threshold;

• Available sensing energy: o For example, the target WTRU may indicate to the anchor WTRU(s) a time and/or frequency resources (e.g., Comb-M configurations, N OFDM symbols and/or Z ms sensing duration) if the total available sensing energy is below a threshold;

• Measurement window indication: o For example, the target WTRU may indicate a SL-PRS periodicity (e.g., periodic with periodicity P1 ms), and/or bandwidth (e.g., X MHz) if the indicated measurement window duration is below a (pre)configured threshold;

• AoD of the configured SL-PRS resources, number of unique spatial beams, beamwidth: o For example, the target WTRU may indicate to the anchor WTRU(s) the resource I D(s) from the set of (pre)configured resources such that difference between the AoDs of the resources in the (pre)configured set and the indicated AoD is below a (pre)configured threshold; and/or o For example, the target WTRU may indicate to the anchor WTRU(s) SL-PRS resource set ID(s) such that difference between configured beamwidth and the indicated beamwidth is below a (pre)configured threshold;

• SL-PRS QCL information: o In one example, the target WTRU may indicate the QCL (e.g., type D) relation with any other RS that may be known to the anchor WTRU(s); and/or o For example, the target WTRU may indicate to the anchor WTRU(s) the SL-PRS resource/resource set I D(s) from the (pre)configured set based on the spatial direction of the known QCL’ed RS; and/or

• QoS requirement: o For example, the target WTRU may indicate SL-PRS time and/or frequency configurations (e.g., N OFDM symbols, comb-M configuration, X MHz bandwidth allocation) if the QoS requirement (e.g., accuracy) is above a (pre)configured threshold, and/or o For example, the target WTRU may indicate a periodicity P1 if the above QoS latency requirement is above a (pre)configured threshold, and P2 otherwise.

[0353] In one example, the target WTRU may (e.g., implicitly) indicate the SL-PRS configurations based on (e.g., at least) any of the following (e.g., that may already be available to the anchor WTRU(s)):

• Target WTRU location: o For example, the target WTRU may indicate to the anchor WTRU(s) a transmission power (e.g. Y dBm) and/or frequency allocation (e.g., comb-M, X MHz bandwidth) if the distance between the target WTRU and the anchor WTRU(s) is above a (pre)configured threshold. The WTRU may indicate another set of parameters otherwise;

• Obstacle location: o For example, the target WTRU may indicate to the anchor WTRU(s) a subset of (pre)configured SL-PRS resources (e.g., SL-PRS resource set ID(s), SL-PRS resources I D(s)) such that the difference between the AoD of the SL-PRS resources I D(s) and the AoD between the target WTRU and the obstacle is below a (pre)configured threshold, and/or o For example, the WTRU may indicate to the anchor WTRU(s) the SL-PRS configuration (e.g., SL-PRS resource set ID(s)) with small beamwidth if the distance between the target WTRU and the obstacle is above a (pre)configured threshold; the target WTRU may indicate the configuration with large beamwidth otherwise;

• Obstacle velocity: o For example, the target WTRU may indicate to the anchor WTRU(s) beamwidth configuration (e.g., X1 MHz) if the obstacle velocity is above a (pre)configured threshold; the target WTRU may indicate another set of beamwidth (e.g., X2 MHz) otherwise, and/or o For example, the target WTRU may indicate to the anchor WTRU(s) a bandwidth allocation (e.g., X1 MHz) and/or sensing duration (e.g. Y ms) if the obstacle velocity is above a (pre)configured threshold.

• Uncertainty in obstacle location: o For example, the target WTRU may indicate to the anchor WTRU(s) a beamwidth configuration (e.g., X1 MHz) if the uncertainty in the obstacle location is above a (pre)configured threshold, and another configuration (e.g. X2 MHz) otherwise, and/or o For example, the target WTRU may indicate to the anchor WTRU(s) the SL-PRS configuration (e.g., SL-PRS resource I D(s), SL-PRS resource set ID(s)) such the difference between the AoD of the configured SL-PRS resources and the AoD range of the obstacle including the uncertainty range is below a (pre)configured threshold.

[0354] In certain representative embodiments, a (e.g., target) WTRU may transmit the SL-PRS resources and receive a measurement report.

[0355] In one example, a WTRU may transmit the configured SL-PRS resources at the indicated time and frequency resources.

[0356] In one example, a target WTRU may receive information indicating (e.g., at least) any of the following in a measurement report:

• Obstacle location and/or the associated uncertainty range,

• Obstacle velocity and/or the associated uncertainty range,

• The measurements associated with the obstacle (e.g., RTT, AoA, RSRP )

• The uncertainties in the measurements associated with the obstacle, and/or

• Timestamp associated with the obstacle location and/or velocity measurements

[0357] In one example, a target WTRU may forward a measurements report from an anchor WTRU(s) to the network. The target WTRU may (e.g., also) report (e.g., at least) any of the following to the network:

• SL-PRS transmission time along with the SL-PRS I D(s),

• Bistatic RTT thresholds (e.g., thresholdjnax and/or threshold_min), and/or • Indicated priority to the obstacle

[0358] In one example, a target WTRU may use (e.g., at least) any of DCI, MAC-CE, RRC, SLPP, and/or LPP messages to perform obstacle measurement reporting to the network.

[0359] In one representative embodiment a WTRU may receive SRSp and SL-PRS configuration information from the network (e.g., for sensing). The WTRU may detect an obstacle, such as via SRSp measurements from monostatic sensing. The WTRU may determine the time thresholds (threshold_min, thresholdjnax) based on its transmission capabilities (e.g., transmission power, bandwidth) and/or requirements (e.g., QoS requirement). The WTRU may send a discovery message which includes WTRU location, obstacle location, and/or sensing zone (e.g., maximum sensing radius) information to the anchor WTRUs. The WTRU may receive a response from an anchor WTRU(s) with assistance data, such as anchor WTRU location. The WTRU may select the anchor WTRU for bistatic sensing, such as based on the expected RTT (e.g., determined based on the anchor WTRU location and obstacle location) is above a first threshold, such as threshold_min (e.g., outside of an ambiguity range) and below a second threshold, such as thresholdjnax (e.g., below a maximum range). The WTRU may send a request for bistatic sensing to any selected anchor WTRU(s). The request may include information indicating a measurement window (e.g., start time, duration). After the anchor WTRU(s) accept the bistatic sensing request (e.g., a “Yes”), the WTRU may indicate one or more of the SL-PRS configurations to the anchor WTRU(s), such as via threshold_min and thresholdjnax (e.g., sensing coverage area). The WTRU may transmit the configured SL-PRSs to the anchor WTRU(s). The WTRU may receive a report with obstacle location from the anchor WTRU(s).

[0360] TRP Selection for gNB-based Bistatic Sensing

[0361] TRP Selection for Bistatic Sensing

[0362] In certain representative embodiments, a WTRU (e.g., target WTRU) may select the TRPs for UL and/or DL bistatic sensing.

[0363] In one example, a target WTRU may be configured to select suitable TRPs for DL and/or UL bistatic sensing from a set of (pre)configured TRPs. The target WTRU may select a TRP based on (e.g., at least) any of the following:

• The expected bistatic RTT associated with the TRP is below the (pre)configured thresholdjnax,

• The expected bistatic RTT associated with the TRP is above the (pre)configured threshold_min, and/or

• The distance between the TRP and the obstacle is below a (pre)configured threshold.

[0364] In one example, the WTRU may be configured to select a total N number of TRPs for DL and/or UL bistatic sensing. In one example, the number N may correspond to the TRPs required to perform the intended sensing method (e.g., 3 TRPs for RTT) and hence be associated with the method. [0365] If the number of TRPs fulfilling the TRP selection conditions (e.g., M) is above N (e.g., M > N , the WTRU may down select (e.g., reduce) the number of TRPs (e.g., for DL and/or UL bistatic sensing methods) based on prioritization for certain criteria. The WTRU may choose N TRPs based on (e.g., at least) any of the following criteria:

• The N TRP(s) with smallest distance to the target WTRU,

• The N TRP(s) with the difference in expected AoD to the obstacle above a (pre)configured threshold, and/or

• The N TRP(s) with the lowest DL/UL expected bistatic RTT

[0366] In certain representative embodiments, a WTRU (e.g., target WTRU) may receive a request form the network to initiate bistatic sensing.

[0367] In one example, a WTRU may receive a request from the network (e.g., LMF, gNB) to perform sensing. The WTRU may receive a request in a semi-static message (e.g., RRC, LPP).

[0368] In one example, the WTRU may receive an estimate of the location (e.g., coarse estimate of the obstacle location) from the network. If the WTRU does not receive an estimate of the location from the network, the WTRU determines the location of the obstacle if the WTRU based sensing method is configured or measurements to the network if the NW assisted sensing method is configured. If the WTRU cannot determine the location of the obstacle, the WTRU may report a cause to the network as a response for the request (e.g., a cause can be the reason why the WTRU cannot find the obstacle (e.g., no multipath measurements are found), a cause can be a response indicating that the WTRU cannot find the obstacle).

[0369] In certain representative embodiments, a WTRU (e.g., target WTRU) may request the network for gNB-based bistatic sensing.

[0370] In one example, a target WTRU may request the network to assist it in obstacle sensing. The request may be triggered by (e.g., at least) any of the following conditions:

• The target WTRU determines the conditions concerning the WTRU’s detection of an obstacle (e.g., decrease in communication performance above a (pre)configured threshold, decrease in the positioning performance below a (pre)configured threshold),

• The obstacle priority is above a (pre)configured threshold,

• The difference in obstacle location between multiple measurement occasions is above a (pre)configured threshold,

• The decrease in SRSp RSRP if the target WTRU is performing monostatic sensing between multiple measurement occasions is above a (pre)configured threshold,

• The velocity of the obstacle is above a (pre)configured threshold, and/or

• The target WTRU’s coverage changes from out-of-coverage to in coverage. [0371] In one example, the WTRU may receive triggering information in a PRS and/or SRSp (pre)configuration from the network.

[0372] In certain representative embodiments, a WTRU (e.g., target WTRU) may selects its role (e.g., transmitter/receiver) for bistatic sensing.

[0373] In one example, the target WTRU may (e.g., also) indicate a preferred role of sensing (e.g., DL bistatic sensing, UL bistatic sensing).

[0374] In one example, a target WTRU may decide to perform DL bistatic sensing based on (e.g., at least) any of the following conditions:

• The expected bistatic RTT is below the (pre)configured DL thresholdjnax,

• The expected bistatic RTT is above the (pre)configured DL threshold_min,

• The expected bistatic RTT is above the (pre)configured UL thresholdjnax,

• The total number of determined suitable TRPs for DL bistatic sensing is above the (pre)configured threshold (e.g., M > N, where N is the threshold),

• The distance between the WTRU and the obstacle is above a (pre)configured threshold,

• The velocity of the obstacle is above a (pre)configured threshold,

• The QoS requirement (e.g., accuracy) is above a (pre)configured threshold,

• The uncertainty of the obstacle location and/or velocity is above the (pre)configured threshold, and/or

• The energy availability of the target WTRU is below the (pre)configured threshold

[0375] FIG. 12 is a system diagram illustrating differences in sensing coverage areas for uplink and downlink sensing.

[0376] For example, the transmission power and hence the maximum sensing range in the DL may be more than the maximum sensing range in the UL, as illustrated in FIG. 12. The WTRU 102 may request the TRP(s) 502 to perform DL-PRS transmission for sensing in cases where the WTRU determines that an obstacle is out of range of its maximum bistatic sensing range.

[0377] For example, since the transmission power may (e.g., also) be associated with the accuracy of the obstacle location and/or velocity estimation, the target WTRU may (e.g., also) determine to request the TRP to perform DL sensing in the cases where the accuracy requirement and/or the uncertainty in obstacle location and/or velocity is above a (pre)configured threshold.

[0378] In another example, a target WTRU may decide to perform UL bistatic sensing based on (e.g., at least) any of the following conditions:

• The expected bistatic RTT is below the (pre)configured UL bistatic thresholdjnax,

• The expected bistatic RTT is above the (pre)configured UL bistatic threshold_min,

• The expected bistatic RTT is above the (pre)configured DL bistatic thresholdjnax, • The total number of determined suitable TRPs for UL bistatic sensing is above the (pre)configured threshold (e.g., M > N),

• The QoS requirement (e.g., accuracy) is below the (pre)configured threshold,

• The uncertainty in the obstacle location and/or velocity is below the (pre)configured threshold, and/or

• The energy availability of the target WTRU is above the (pre)configured threshold

[0379] In the uplink bistatic sensing scenario, the WTRU may have a smaller transmission power. Hence, it may determine to select this mode or preference in the cases where a detected obstacle is within the bistatic range of the WTRU and the TRP.

[0380] Similarly, it may want to perform uplink sensing if it determines that the total energy available for sensing is above a required (pre)configured threshold.

[0381] In another example, the WTRU may determine to perform a two-way sensing (e.g., both DL and UL sensing) based on (e.g., at least) any of the following:

• The expected bistatic RTT is below the (pre)configured DL bistatic thresholdjnax,

• The total number of determined suitable TRPs for UL bistatic sensing is above the (pre)configured threshold (e.g., M > N), and/or

• The QoS requirement (e.g., accuracy) is above the (pre)configured threshold.

[0382] In another example, the WTRU may be configured by the network with its role for sensing.

[0383] In certain representative embodiments, a WTRU (e.g., target WTRU) may send an on-demand DL and/or UL bistatic sensing request.

[0384] In one example, the target WTRU may determine to send an on-demand request to the network for DL/UL bistatic sensing if (pre)configured. The WTRU may use at least one of the signals (e.g., UCI, MAC- CE, RRC, LPP) to send the request to the network. The request may include (e.g., at least) any of the following:

• The preferred role for bistatic sensing (e.g., DL bistatic sensing, UL bistatic sensing),

• The selected set of M TRPs (e.g., TRP IDs),

• Bistatic thresholds (e.g., threshold_min, thresholdjnax) per TRP (e.g., if determined autonomously by the target WTRU), and/or

• Expected bistatic RTT per TRP

[0385] In certain representative embodiments, a WTRU (e.g., target WTRU) may receive a bistatic sensing request acceptance response. [0386] In one example, a target WTRU may receive a response from the network in one of the downlink signals (For example, DCI, MAC-CE, RRC, LPP).

[0387] In one example, the WTRU may receive an acceptance message (e.g., ACK, “Yes”) from the network, indicating that it has accepted the bistatic request from the WTRU including the requested or preferred mode (e.g., UL and/or DL) and the TRPs.

[0388] In another example, the WTRU may receive an acceptance message (e.g., ACK, “Yes”) from the network and may receive a (e.g., new or modified) set of TRPs and/or sensing mode from the network other than that requested by the target WTRU.

[0389] In both the cases, the WTRU may determine the configurations for transmission or reception based on this indication.

[0390] In certain representative embodiments, a WTRU (e.g., target WTRU) may perform fallback operations in cases of request rejection.

[0391] In one example, a WTRU may receive a rejection message (e.g., NACK, “No”) from the network indicating that the request for bistatic sensing has been rejected. In such cases, the target WTRU behavior may be characterized by (e.g., at least) any of the following:

• The target WTRU may determine to perform/continue to perform monostatic sensing,

• The target WTRU may determine to discover anchor WTRUs in the vicinity and request sidelink based bistatic sensing, and/or

• The target WTRU may determine to terminate the sensing procedure.

[0392] DL-PRS/SRSp Configuration

[0393] In certain representative embodiments, a WTRU (e.g., target WTRU) may receive (e.g., an indication of) a DL-PRS configuration.

[0394] In one example, a target WTRU may be configured to perform DL bistatic sensing in cases of acceptance of the bistatic sensing request.

[0395] In one example, a target WTRU may receive DL-PRS configurations explicitly from the TRPs, such as including the time, frequency, periodicity, DL-PRS resource IDs, DL-PRS resource set IDs The WTRU may (e.g., also) receive a measurement window including at (e.g., at least) any of the following parameters:

• Start or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point),

• Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds), and/or

• Periodicity of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds). [0396] The target WTRU may receive an indication from the network (e.g., DCI/MAC-CE indication) for initiating the DL-PRS transmission. [0397] In another example, if the WTRU is (pre)configured with any on-demand DL-PRS configurations, the WTRU may receive an indication (e.g., DCI/MAC-CE indication) from the network of activation of the set or subset of the on-demand configurations.

[0398] In one example, a target WTRU may (e.g., further) implicitly determine the subset of on-demand configurations based on (e.g., at least) any of the following assistance information indicated to the target WTRU:

• TRP IDs: o For example, the WTRU may determine the subset from the set of on-demand DL-PRS configurations corresponding to the TRP IDs indicated to the target WTRU;

• Obstacle location: o For example, the WTRU may determine the subset from the set of on-demand DL-PRS configurations (e.g., PRS resource ID(s), DL resource set ID(s)) such that the difference between the AoD of the PRS resources and the expected AoD to the obstacle is below a (pre)configured threshold; and/or

• Uncertainty in obstacle location: o For example, the WTRU may determine the subset from the set of on-demand DL-PRS configuration (e.g., DL-PRS resource set ID(s)) with large beamwidths if the uncertainty in the obstacle location is above a (pre)configured threshold, and/or o For example, the WTRU may determine the subset from the set of on-demand DL-PRS resources (e.g., DL-PRS resource ID(s)) if difference between the AoD of the PRS resources and the expected AoD to the obstacle (pre)configured threshold.

[0399] In another example, a WTRU may implicitly determine the DL-PRS configurations from a set of (pre)configured resources based on (e.g., at least) any of the following:

• Validity time: o For example, the target WTRU, if preconfigured with the validity time for a set of configurations and/or the TRP IDs, may determine the valid DL-PRS configuration based the current time and the time duration where the DL-PRS configurations may have been valid. For example, if TRP 1 is invalid at the current time instance, the target WTRU may not choose the configurations associated with TRP 1 ;

• Thresholdjnax,

• Thresholdjnin,

• Expected bistatic RTT,

• Obstacle location,

• Obstacle velocity, • Uncertainty in obstacle location, and/or

• Target WTRU location.

[0400] In the above, the associations between the parameters and the configurations may be the same as in the case of implicit SL-PRS indications and may be reused here by replacing the anchor WTRU(s) with TRP(s) and “SL-PRS” with “DL-PRS”.

[0401] In addition, the WTRU may receive assistance data from the network with indications of the activated DL-PRS configurations from the set of (pre)configured configurations. The WTRU may use (e.g., at least) any of the following assistance information to determine the DL-PRS configurations:

• Configuration ID(s): o For example, in case the target WTRU is (pre)configured with multiple sets of DL-PRS configurations where each associated with the configuration ID, the WTRU may be indicated with the selected configuration ID, o In one example, the WTRU may determine that the configured PRS resources may either partially or totally correspond to the indicated configuration ID, and/or o In one example, if the is indicated with multiple configuration I D(s), the WTRU may determine that the DL-PRS configuration may be a combination of the multiple (pre)configured configurations;

• Number of TRPs, TRP I D(s)/location indication: o For example, the WTRU may determine the DL-PRS configurations (e.g., DL-PRS resource ID(s), DL-PRS resource set ID(s)) from the set of (pre)configured configurations corresponding to the indicated TRP I D(s) in the assistance information, o For example, the WTRU may infer DL-PRS comb size and hence the frequency density based on the configured number of TRPs (e.g., 3 TRPs may correspond to Comb-2 or 4 configurations), and/or o For example, the WTRU may determine the total number of symbols in the configuration based on the number of configured TRPs. For example, N TRPs may correspond to a specific set of frequency domain resource allocation (e.g., Comb-N, bandwidth X MHz) and/or time allocation (e.g., Y number of OFDM symbols per resource);

• One or more combinations of DL-PRS periodicity, bandwidth, sensing duration, time offset, comb patterns;

• Available sensing energy;

• Measurement window indication;

• AoD of the configured resources, number of unique spatial beams, beamwidth;

• DL-PRS QCL information; and/or • QoS requirement.

[0402] In the above, the associations between the assistance information parameters and the configurations may be the same as in the case of implicit SL-PRS indication and may be reused here by replacing the anchor WTRU(s) with TRP(s) and “SL-PRS” with “DL-PRS”.

[0403] In one example, a target WTRU may be configured with a measurement window for the configured DL-PRS resources reception.

[0404] In another example, a WTRU may receive an indication from the network activating a measurement window from a (pre)configured set of multiple measurement windows. In one example, the WTRU may receive an activation indication using (e.g., at least) any of a measurement window ID, measurement start time, measurement duration

[0405] In another example, the WTRU may implicitly determine the measurement window based on the configured or determined DL-PRS resources.

[0406] The WTRU may receive and measure the DL-PRS resources upon transmission.

[0407] In certain representative embodiments, a WTRU (e.g., target WTRU) may receive and measure the configured DL-PRS resources.

[0408] In one example, a target WTRU may receive configured DL-PRS resources from the TRP(s) at the indicated time, frequency resources.

[0409] In one example, the WTRU may measure at least one of the ToA, RSTD, AoA, RSRP, RSRPP, doppler shift from the received signals at the indicated time and frequency resources.

[0410] In one example, the WTRU may be configured to estimate the obstacle location. The target WTRU may use the measurements to determine the obstacle location and/or velocity.

[0411] In one example, the target WTRU may be configured to report (e.g., at least) any of the following:

• Measurements from the received DL-PRS resources (e.g., ToA, RSTD, AoA, RSRP, RSRPP, doppler shift ),

• Timestamp of measurements,

• Obstacle location and/or the associated uncertainties,

• Obstacle velocity and/or the associated uncertainties,

• Reference values (e.g., reference TRP for RSTD measurements), and/or

• Target WTRU Orientation (e.g., reference for AoA measurement)

[0412] In certain representative embodiments, a WTRU (e.g., target WTRU) may determine a SRSp configuration.

[0413] In one example, a WTRU may be configured to perform UL bistatic sensing in case of acceptance of the bistatic sensing request. In one example, the request may indicate a sensing method (e.g., RTT based UL sensing, RTT based two-way sensing). [0414] In another example, the WTRU may receive SRSp configurations for UL bistatic sensing explicitly from the network including information indicating (e.g., at least) any of time, frequency, periodicity, SRSp resource IDs, SRSp resource set IDs

[0415] In another example, the WTRU may determine the SRSp resources from a set of (pre)configured SRSp resources based on the conditions similar to the ones for SL-PRS configuration by replacing the anchor WTRU(s) with the TRP(s) and SL-PRS configuration parameters (e.g., SL-PRS resource ID(s), SL-PRS resource set ID(s)) with SRSp configuration parameters (e.g., SRSp resource ID(s), SRSp resource set ID(s)).

[0416] In one example, the WTRU may determine a subset of SRSp configurations, or SRSp resources, which are spatially aligned with received DL-PRS (e.g., for two-way RTT based bistatic sensing). For example, if the WTRU determines the obstacle location (e.g., based on measurements on DL-PRS), based on (e.g., at least) any of the determined obstacle location, TRP locations, and/or expected bistatic RTT, the WTRU may determine threshold_min and thresholdjnax. Based on the determined thresholdjnin and thresholdjnax, the WTRU may determine a spatial transmission direction of SRSp (e.g.., spatial transmission direction of SRSp is within thresholdjnin and thresholdjnax). The WTRU may determine which SRSp resource(s) to use, where each resource is associated with a beam direction (e.g., expressed in terms of DL RS such as CSI-RS resource ID, DL PRS resource ID). If there are multiple SRSp resources for transmission, the WTRU may determine to transmit SRSp starting with the lowest index number.

[0417] In one example, threshold_min and threshold nax may be expressed in meters and/or angles. For example, threshold_min and thresholdjnax may be 5 degrees and 30 degrees, respectively.

[0418] In certain representative embodiments, a WTRU (e.g., target WTRU) may transmit the configured SRSp resources.

[0419] In one example, the WTRU may transmit the configured SRSp resources at the indicated time and frequency resources.

[0420] In one example, the target WTRU may report the measurements to the network including (e.g., at least) any of the following:

• UL bistatic threshold (e.g., UL bistatic thresholdjnax, UL bistatic thresholdjnin), and/or

• The SRSp transmission timestamp along with the SRSp I D(s)

[0421] In one example, the target WTRU may receive the obstacle location from the network.

[0422] FIG. 13 is a system diagram illustrating a SRSp configuration for UL bistatic sensing based on obstacle location.

[0423] In a representative embodiment, a WTRU 102 (e.g., target WTRU 902) may receive candidate SRSp configuration information from the network (e.g., LMF, gNB) with obstacle location and associated uncertainty range for sensing. The WTRU 102 may determine an SRSp configuration (e.g., out of the candidate SRSp configurations provided by the network) based on the obstacle 202 location and associated uncertainty range. The WTRU may indicate the configured resources (e.g., time, frequency) to the network. The WTRU may transmit the determined SRSp resources for bistatic sensing.

[0424] FIG. 14 is a system diagram illustrating TRP selection for bistatic sensing. In FIG. 14, the target WTRU 902 may select TRP 1 502a as the obstacle lies within an ambiguous zone of TRP 2 502b.

[0425] In a representative embodiment, a WTRU (e.g., target WTRU) may receive candidate SRSp configuration information from the network for monostatic sensing including the time thresholds (e.g., threshold_min, thresholdjnax). The WTRU may detect an obstacle (e.g., via measurements from reflected SRS). The WTRU may report the obstacle location and its location to the network. The WTRU may select one or more TRPs for bistatic sensing if the expected RTT (e.g., determined based on the TRP location and obstacle location) is above threshold_min (e.g., outside of the ambiguity range) and below thresholdjnax (e.g., below the maximum range). The WTRU may send an on-demand request with any selected TRPs, obstacle and its location to perform bi-static sensing. The WTRU may receive ACK information from the network indicating TRPs to perform UL sensing. The WTRU may determine an SRSp configuration (e.g., out of the candidate SRSp configurations provided by the network) based on threshold_min and thresholdjnax (e.g., sensing coverage area). The WTRU may transmit the determined SRSp resources for bistatic sensing.

[0426] Group-based Sensing

[0427] Discovery Procedure

[0428] In certain representative embodiments, a WTRU (e.g., target WTRU) may receive a request for group-based sensing.

[0429] In one example, the discovery message for sensing group formation may either be triggered by request from an anchor WTRU, the WTRU (e.g., server WTRU or any other WTRU capable and authorized to perform discovery procedure, anchor WTRU selection, sidelink resource allocation), or by a request from the network. In all the cases, the trigger condition may or may not be the obstacle detection.

[0430] In one example, a WTRU may receive a request for discovery initiation for sensing group formation from an anchor (e.g., target WTRU) WTRU, such as via sidelink specific lower and higher layer signalling (e.g., SCI, SL-MAC-CE, PC5-RRC message). For example, the WTRU may receive (e.g., at least) any of the following in the discovery request:

• Anchor WTRU information: o Anchor WTRU ID (e.g., RNTI), or any other IDs that are used to identify the anchor WTRU, o Anchor WTRU location and/or the associated uncertainty range, o Anchor WTRU velocity and/or the associated uncertainty range, o Anchor WTRU coverage information (e.g., in coverage, cell ID) o Anchor WTRU sensing zone (e.g., maximum monostatic RTT threshold), o (Maximum) transmission power, o Synchronization source information (e.g., time/frequency/phase synchronization), o Supported frequency range (e.g., FR1, FR2) and/or subcarrier spacing and/or (maximum) bandwidth for SL-PRS, and/or o Anchor WTRU Duplexing information (e.g., full duplex WTRU);

• Obstacle information: o Obstacle location and/or uncertainty range, o Obstacle velocity and/or uncertainty range, and/or o How the obstacle location is determined (e.g., by network, by monostatic sensing);

• Anchor WTRU capabilities: o (Maximum) transmit power, o Supported sensing measurement (e.g., time, angle, velocity, range ), o Supported number of obstacles, o Available start time and sensing duration, and/or o Available anchor WTRU energy; and/or

• Anchor WTRU request for group: o Number of anchor WTRUs in the group (e.g., minimum number, maximum number), and/or o QoS requirement for obstacle location (e.g., accuracy, latency, reliability requirements).

[0431] In one example, a WTRU may determine to initiate a discovery procedure for sensing group formation based on (e.g., at least) any of the following:

• The distance between the anchor WTRU and the located obstacle is below a (pre)configured threshold,

• The reported obstacle velocity is above a (pre)configured threshold,

• The reported uncertainty in obstacle location and/or velocity is above a (pre)configured threshold,

• The transmission/reception bandwidth capability of the anchor WTRU is above a (pre)configured threshold, and/or

• The available sensing duration is above a (pre)configured threshold

[0432] In another example, the WTRU (e.g., the server WTRU) may determine to initiate a discover procedure autonomously sensing group formation based on (e.g., at least) any of the following triggering conditions:

The WTRU satisfies at least one of the conditions concerning the detection of an obstacle,

The distance between the WTRU and the located obstacle is below a (pre)configured threshold,

The velocity of the located obstacle is above a (pre)configured threshold, • The indicated obstacle priority is above a (pre)configured threshold,

• The uncertainty in obstacle location is above a (pre)configured threshold, and/or

• The uncertainty in obstacle velocity is above a (pre)configured threshold

[0433] In another example, the WTRU may receive a request from the network to initiate a discovery procedure for sensing group formation. The WTRU may receive the request via lower and/or higher layer signalling (e.g., DCI, MAC-CE, RRC, SLPP, LPP message).

[0434] In certain representative embodiments, a WTRU may send a discovery message for group formation.

[0435] In one example, a WTRU may determine to initiate the discovery procedure for sensing group formation. The WTRU may broadcast a discovery message to other WTRUs in its vicinity, such as via PC5 interface or any other interface (e.g., RRC) allowing connection between the WTRUs.

[0436] In one example, the WTRU may transmit (e.g., at least) any of the following in the discovery message:

• Requesting anchor WTRU information (if the discovery procedure was initiated by the anchor WTRU) including (e.g., at least) any of: o Anchor WTRU ID (e.g., RNTI), or any other IDs that are used to identify the anchor WTRU, o Anchor WTRU location and/or the associated uncertainty range, o Anchor WTRU coverage information (e.g., in coverage, cell ID) o Anchor WTRU sensing zone (e.g., maximum monostatic RTT threshold), o Anchor WTRU (maximum) transmission power, o Anchor WTRU synchronization source information (e.g., time/frequency/phase synchronization), and/or o Supported frequency range (e.g., FR1, FR2) and/or sub-carrier spacing and/or (maximum) bandwidth for SL-PRS;

• Obstacle information (e.g., if the discovery procedure was triggered by obstacle detection) including (e.g., at least) any of: o Obstacle location and/or uncertainty range and/or obstacle location timestamp, o Obstacle velocity and/or uncertainty range and/or location timestamp, o QoS requirement for obstacle location (e.g., accuracy, latency, reliability requirements), and/or o How the obstacle location is determined (e.g., by network, by monostatic sensing); and/or

• Required WTRU capabilities to be included in the group such as (e.g., at least) any of: o Capability to estimate its location and/or orientation, o Capability to perform sidelink measurements (e.g., time, angle, frequency, frequency shift), o Capability to perform a specific positioning methods (e.g., RTT), o Capability to obtain location coordinates from the measurements, o Capability to report its location and orientation to the network, WTRU (e.g., server WTRU), o Capability to report the obstacle(s)’ location to the network, WTRU (e.g., server WTRU), o Capability to report the measurements to the network, WTRU (e.g., server WTRU) o Required sensing start time and duration threshold, o Required resolution threshold for time related positioning methods (e.g., RTT, TDoA) threshold, o Required resolution threshold for angle related positioning methods (e.g., AoD, AoA), o Required resolution threshold for velocity related positioning methods, o Minimum WTRU energy threshold, and/or o Minimum WTRU complexity threshold

[0437] In certain representative embodiments, a WTRU may receive a discovery response and/or assistance information.

[0438] In one example, a WTRU may (e.g., also) request assistance information to be sent by the anchor WTRU(s) upon discovery in the discovery message including the anchor WTRU information and/or capabilities.

[0439] In one example, a target WTRU may receive a response to the discovery message upon determining its suitability for sensing based on the information from the WTRU. The WTRU may (e.g., also) receive a set of assistance information including (e.g., at least) any of the following:

• Responding anchor WTRU information, such as (e.g., at least) any of: o Anchor WTRU ID (e.g., RNTI), o Anchor WTRU type (e.g., vehicle, mobile phone) o Anchor WTRU location and/or its uncertainty, o Anchor WTRU velocity and/or its uncertainty, o Anchor WTRU coverage information (e.g., in coverage, out of coverage, cell ID), and/or o Anchor WTRU Duplexing information (e.g., full duplex WTRU); and/or

• Responding anchor WTRU capability information, such as (e.g., at least) any of: o (Maximum) transmit power, o Supported positioning methods, o Supported number of obstacles, o Available sensing start time and duration, and/or o Available WTRU energy [0440] Group formation and procedures

[0441] In certain representative embodiments, a WTRU may form a group of anchor WTRUs for sensing. [0442] FIG. 15 is a system diagram illustrating group formation with respect to a reference location 1502 and group distance threshold information 1504.

[0443] In one example, a (e.g., server) WTRU 102 may form a group 1506 of anchor WTRUs for sensing based on the reception of a discovery response and/or assistance information from the anchor WTRU(s) 102a, 102b, 102c, 102d. The WTRU 102a may use (e.g., at least) any of the following criteria for determining whether to include an anchor WTRU in the group for sensing:

• The distance of the responding anchor WTRU(s) from the requesting anchor WTRU is below a (pre)configured threshold (e.g., group distance threshold), o For example, the WTRU may be (pre)configured threshold (e.g., X meters) and depending on the location of the responding anchor WTRU(s), o In one example, the threshold may be (pre)configured to the WTRU by the network, o In another example, the threshold may be determined autonomously by the WTRU. For example, the WTRU may determine a group distance threshold of X1 meters (e.g., 80 meters) in case of at least one of the following conditions:

■ the number of responding anchor WTRUs is above a (pre)configured threshold,

■ the (maximum) transmission power of the anchor WTRUs is above a (pre)configured threshold,

■ the obstacle velocity is above a (pre)configured threshold, and/or

■ the uncertainty in obstacle location is above a (pre)configured threshold, o The WTRU may determine another group distance threshold of X2 meters (e.g., 30 meters) otherwise;

• The distance of the discovered anchor WTRU(s) from an indicated location is below a (pre)configured threshold (e.g., group distance threshold), o For example, the WTRU may determine a sensing zone where the WTRU may be interested in sensing the obstacle, for example, as illustrated in FIG. 15. In one example, the sensing zone may be an area (e.g., a cell, sector, circle ) indicated by a reference 2D or 3D coordinate (e.g., centre of the area) or a reference 2D/3D location coordinate. The WTRU may determine this zone by one or more combinations of the following:

■ The area location reported by the requesting anchor WTRU for obstacle location,

■ The area location where the obstacle is detected by the WTRU (e.g., between two entities (e.g., TRPs, WTRUs), cell/sector of aTRP where the obstacle was detected) if the discovery was triggered by obstacle location, and/or The area location where the WTRU may be configured by the network to locate an obstacle;

• The velocity of the discovered anchor WTRU is below a (pre)configured threshold, o For example, the WTRU may prefer the anchor WTRU(s) with a below threshold velocity due to one or more of the following:

■ The sensing group and/or sub-group may be more stationary (e.g., where the anchor WTRUs are in the same location) for an extended period of time, and/or

■ The anchor WTRU may not be required to report its location frequently (e.g., periodically),

• The relative velocity of the discovered anchor WTRU with the group reference velocity is below a (pre)configured threshold;

• The maximum transmit power of the discovered anchor WTRU is above a (pre)configured threshold, o For example, the WTRU may determine the anchor WTRU(s) with above threshold transmission power in order so that the monostatic and the bistatic coverage area within the group is maximized. This may result from the fact that if the transmission power is higher, there are more suitable bistatic sensing pairs within the group;

• The uncertainty in the discovered anchor WTRU location is below a (pre)configured threshold, o For example, the uncertainty in WTRU location can cause error propagation to the obstacle location as well;

• The synchronization of the anchor WTRU is known, o For example, if the anchor WTRU may be selected in the group if:

■ The synchronization source of the discovered anchor WTRU (e.g., TRP, any other entities with accurate reference time) is same as the WTRU, and/or

■ The synchronization source (e.g., clock offset) of the discovered anchor WTRU is known to the WTRU;

• The available sensing duration of the discovered anchor WTRU is above a (pre)configured threshold; and/or

• The available energy of the discovered anchor WTRU is above a (pre)configured threshold.

[0444] In certain representative embodiments, a WTRU may transmit a group indication and/or assistance information to the group of anchor WTRUs.

[0445] In one example, the WTRU may indicate the group and/or assistance information to the selected anchor WTRUs in the sensing group, such as via sidelink specific lower and/or higher layer signalling (e.g., SCI, SL-MAC-CE, PC5-RRC message). In one example, the WTRU may either (e.g., at least) any of the following group and/or assistance information to the group of anchor WTRUs: • Group ID: o The WTRUs in the group may be assigned with the unique group IDs in order to associate the SL-PRS transmissions, measurements, estimations, sessions with the group, o In one example, the WTRU may be (pre)configured with the group IDs from the network, and/or o In another example, the WTRU may generate group IDs and allocate it to the anchor WTRUs in the group;

• Anchor WTRU(s) information: o Anchor WTRU ID(s), o Locations of the anchor WTRU(s) in the group and/or the associated uncertainties range, and/or o Velocities of the anchor WTRU(s) in the group and/or the associated uncertainties range;

• Obstacle information: o Obstacle location and/or the associated uncertainty range, and/or o Obstacle velocity and/or the associated uncertainty range; and/or

• Group sensing window: o The WTRU may determine the total time duration which may be dedicated to the group for group-based sensing. The WTRU may indicate the group sensing duration with at least:

■ Start or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point), and/or

■ Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds).

[0446] In certain representative embodiments, a WTRU may (pre)configure the sensing group with one or more SL-PRS configurations.

[0447] In one example, a WTRU may (pre)configure the anchor WTRUs in the group with more than one set of SL-PRS configuration parameters for obstacle location estimation. The (pre)configuration may include (e.g., at least) any of transmission and/or reception configurations. Each transmission and/or reception configuration may be specific to one or more WTRU(s), such as by indication using WTRU I D(s), or SL-PRS resource ID specific to a WTRU, or may be a common configuration (e.g., without any specificity to any WTRU).

[0448] In one example, the WTRU may indicate the configuration to the anchor WTRUs in the group via (e.g., at least) any of the following:

• (Pre)configure via resource pools: o For example, the WTRU may (pre)configure the anchor WTRUs in the group with one or more set of resource pools where each resource pool may contain one or more than one SL-PRS transmission and/or reception parameters, o For example, the WTRU may choose the pool and the SL-PRS configurations within the pool in order to meet the requirements of obstacle location estimation. The WTRU may choose the resource pool with a set of resources (e.g., Comb-M1 configuration, N OFDM symbols per resource ) if the QoS accuracy requirement is below a (pre)configured threshold and/or the energy availability to the anchor WTRU is below a (pre)configured threshold. The WTRU may choose the resource pool with different set of resources otherwise; and/or

• Indicate SRSp (pre)configurations to the anchor WTRUs: o For example, the WTRU may send one or more than one sets of SRSp configurations to the anchor WTRUs in the group, o In one example, each set of configurations may be labelled with a configuration ID, and/or o For example, the (pre)configuration may include (e.g., at least) any of either complete or partial configurations either specific or independent to each anchor WTRUs in the group. The WTRU may then indicate the one or more combinations of the configuration ID which corresponds to the determined SL-PRS configurations.

[0449] In one example, the transmission and/or reception parameters (e.g., either indicated or (pre)configured via resource pools) may include (e.g., at least) any of the SL-PRS resource ID(s), SL-PRS resource set IDs, transmission power, time patterns (e.g., no. of symbols, duration of SL-PRS transmission ), frequency patterns (e.g., comb size, bandwidth, bandwidth allocation), periodicity (e.g., type, number of repetitions), SL-PRS muting patterns, and/or measurement window configurations (e.g., start time, stop time, duration).

[0450] In certain representative embodiments, a WTRU may allocate resources to the group for obstacle detection.

[0451] In one example, the WTRU may configure one or more group anchor WTRUs to detect an obstacle based on at least one of the following conditions:

• The energy availability of the anchor WTRU is above a (pre)configured threshold, and/or

• The transmission power of the anchor WTRU is above a (pre)configured threshold

[0452] In one example, the group of anchor WTRU’s allocated for obstacle detection may or may not be a part of one or more sub-groups within the group, such as may be subject to resource availability (e.g., time, frequency, energy).

[0453] In one example, the WTRU may allocate resources to one or more of the subset of the group of anchor WTRUs for monostatic sensing based obstacle detection based on (e.g., at least) any of: • The group of anchor WTRU(s) are capable to perform full duplex sensing, and/or

• The distance between an anchor WTRU and another anchor WTRU in the group available for obstacle detection is above a (pre)configured threshold

[0454] In one example, the WTRU may allocate at least two or more of the subset of the group of anchor WTRU’s available for bistatic sensing based obstacle detection.

[0455] In one example, the WTRU may determine and allocate roles to each WTRU selected for bistatic sensing based obstacle detection (e.g., transmitting WTRUs, receiving WTRUs). The WTRU may allocate at least one transmitting and at least one receiving WTRU. The WTRU may allocate a transmitting WTRU role to an anchor WTRU based on (e.g., at least) any of the following conditions:

• The transmit power of the anchor WTRU is above a (pre)configured threshold, and/or

• The distance between the anchor WTRU and another transmitting anchor WTRU and/or monostatic sensing WTRU is above a (pre)configured threshold

[0456] In one example, the WTRU may allocate a receiving WTRU role if the conditions listed above are not fulfilled.

[0457] FIG. 16 is a system diagram illustrating WTRU roles and beam transmission patterns for obstacle detection.

[0458] In one example, for the obstacle detection, the WTRU 102 may configure each participating group anchor WTRU 102a, 102b, 102c, 102d with a pattern of beam transmission (e.g., beam pattern) as illustrated in FIG. 16. For example, the WTRU may configure the beams to be transmitted from a lowest SL-PRS ID to the highest. For example, the WTRU may configure the beams to be transmitted from a lowest AoD to the highest.

[0459] In one example, the WTRU may indicate (e.g., at least) any of the following to the group of anchor WTRU(s) selected for obstacle detection (e.g., via unicast):

• Indicated WTRU roles (e.g., monostatic WTRU, bistatic Tx WTRU, bistatic Rx WTRU);

• Configured SL-PRS resources, such as o Time resources (e.g., number of symbols, starting symbol position), o Frequency resources (e.g., number of RBs, starting RE position), and/or o Periodicity (e.g., type, number of repetitions);

• Beam transmission pattern (e.g., beam sweeping);

• Measurement window configuration (e.g., start time, stop time, duration); and/or

• Reporting configuration (e.g., reporting time, reporting periodicity).

[0460] In one example, the WTRU may send (e.g., at least) any of the following assistance information to the group of anchor WTRU(s) allocated for obstacle detection:

• Participating anchor WTRU I D(s), • Anchor WTRU roles,

• SL-PRS resource ID(s),

• SL-PRS resource set I D(s),

• Spatial information of the SL-PRS resource ID(s), and/or

• Beam transmission pattern of the anchor WTRU(s).

[0461] In one example, the WTRU may send an indication (e.g., UCI) to start obstacle detection.

[0462] In one example, the WTRU may receive an indication from the anchor WTRUs in the group for obstacle detection. A target WTRU may receive (e.g., at least) any of the following:

• Obstacle location and/or the associated uncertainty range,

• Obstacle velocity and/or the associated uncertainty range, and/or

• Timestamp of obstacle location.

[0463] In one example, the WTRU may receive a message with information indicating that no obstacle was detected. The WTRU may determine to (i) continue obstacle detection if the remaining group sensing window is above a (pre)configured threshold, or determine to terminate the sensing group.

[0464] Sub-group Formation and Procedures

[0465] In certain representative embodiments, a WTRU may determine to form a sub-group for obstacle sensing.

[0466] In one example, the WTRU may determine to form a sub-group for locating the obstacle based on (e.g., at least) any of the following conditions:

• The WTRU receives a report from the group anchor WTRU(s) of obstacle detection,

• The WTRU receives a report of obstacle detection from other entities (e.g., network, other WTRU(s)),

• The distance between the anchor WTRU in the group and the obstacle is below a (pre)configured threshold,

• The obstacle velocity is above a (pre)configured threshold,

• The uncertainty in obstacle and/or velocity location is above a (pre)configured threshold, and/or

• The remaining duration in the group sensing window is above a (pre)configured threshold.

[0467] In one example, the WTRU may determine requirements of the sub-group including (e.g., at least) any of the following:

• QoS requirement of sensing: o For example, the WTRU may determine the QoS requirement including at least the accuracy (e.g., vertical accuracy, horizontal accuracy), latency, reliability The WTRU may determine a high QoS requirement (e.g., accuracy and/or latency) if:

■ The distance (e.g., average) of the obstacle from the WTRUs in the group is below a (pre)configured threshold, ■ The velocity of the obstacle is above a (pre)configured threshold, and/or

■ The obstacle priority (e.g., average) from the WTRUs in the group is above a (pre)configured threshold o In another example, the WTRU may receive the QoS requirement for sensing from the network;

• Sub-group sensing window: o For example, the WTRU may determine the sub-group sensing duration with (e.g., at least) any of the following parameters:

■ Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds); o For example, the WTRU may determine the sensing window duration (e.g., X ms) based on (e.g., at least) any of the following:

■ The obstacle velocity is below a (pre)configured threshold,

■ The distance (e.g., average) of the obstacle from the WTRUs in the group is below a (pre)configured threshold,

■ The QoS accuracy requirement if above a (pre)configured threshold,

■ The QoS latency requirement is below a (pre)configured threshold, and/or

■ The remaining time in the group sensing duration is above a (pre)configured threshold o The WTRU may determine another sensing window duration (e.g., Y ms) otherwise; and/or

• Total number of WTRUs in the sub-group: o For example, the WTRU may determine total M number (e.g., range including the minimum and maximum number of WTRUs) of the WTRUs in the sub-group-based on (e.g., at least) any of the following:

• The uncertainty in obstacle location is above a (pre)configured threshold,

• The (average) uncertainty in WTRU location is above a (pre)configured threshold,

• The obstacle velocity is above a (pre)configured threshold,

• The uncertainty in obstacle velocity is above a (pre)configured threshold,

• The QoS accuracy requirement is above a (pre)configured threshold,

• The QoS latency requirement is above a (pre)configured threshold, and/or

• The number of WTRUs required in the configured positioning method is above a (pre)configured threshold. [0468] In another example, the WTRU may be configured with the requirements of the sub-group from the network.

[0469] In certain representative embodiments, a WTRU may select the anchor WTRU(s) in the sub-group. [0470] FIG. 17 is a system diagram illustrating sub-group selection for sensing based on obstacle location and sub-group distance threshold information.

[0471] In one example, a (e.g., server) WTRU may select the anchor WTRU(s) 102a, 102b, 102c in the group in the sub-group 1702 as illustrated in FIG. 17. The WTRU may select an anchor WTRU for the sub- groupl 702 based on (e.g., at least) any of the following conditions:

• The distance of the group anchor WTRU 102d to the obstacle 202 is below a (pre)configured threshold (e.g., sub-group distance threshold),

• The uncertainty in the location of the group anchor WTRU 102d is below a (pre)configured threshold,

• The velocity of the group anchor WTRU 102d is below a (pre)configured threshold,

• The difference in the velocities of the group anchor WTRU 102d with a reference anchor WTRU (e.g., first selected anchor WTRU in the sub-group 1702) is below a (pre)configured threshold,

• The available time and/or frequency resources is above a (pre)configured threshold,

• The available sensing of the group anchor WTRU 102d has a duration above a (pre)configured threshold, and/or

• The available energy of the group anchor WTRU 102d is above a (pre)configured threshold.

[0472] In one example, if the total number of selected WTRUs in the sub-group 1702 is determined to be less than M, the WTRU 102 may:

• Resend the discovery message after a (pre)configured T amount of time (e.g., in ms, slots),

• Increase the (pre)configured sub-group distance threshold to include more WTRUs in the sub-group from the group,

• Decrease the (pre)configured requirements (e.g., sensing duration requirement) to include more WTRUs in the sub-group 1702 from the group; and/or

• Deactivate the sensing sub-group.

[0473] In another example, if the total number of WTRUs in the sub-group is determined to be more than a (pre)configured threshold, the WTRU may down select (e.g., reduce) the selected anchor WTRUs in the sub-group (e.g., M) based on prioritization of one or more sub-group formation conditions. For example, the WTRU may be configured and/or determine the WTRUs’ distances to the obstacle as a highest priority. The WTRU may select the M WTRUs with a distance closest to the obstacle.

[0474] In one example, the WTRU may determine the roles for each of the anchor WTRUs (e.g., transmitting WTRU, receiving WTRU) for bistatic sensing within the sub-group. The role determination may be dependent on the configured positioning method, and/or location of the anchor WTRUs in the sub-group In each sub-group, there may be multiple bistatic Tx-Rx pairs. In one example, in each Tx-Rx WTRU pair, there may be multiple transmitting WTRUs for each receiving WTRU and/or multiple receiving WTRUs for each transmitting WTRU.

[0475] In certain representative embodiments, a WTRU may configure the sub-group of anchor WTRUs with SL-PRS configuration information (e.g., resources) for bistatic sensing.

[0476] In one example, the WTRU may determine to configure SL-PRS resources (e.g., Tx configurations, Rx configurations) for each of the WTRUs in the sub-group. In one example, the WTRU may determine to

• choose one or more subsets of SL-PRS configurations for the WTRUs in the sub-group from the set of (pre)configured resources, and/or

• choose one or more subsets of SL-PRS configurations for the WTRUs in the sub-group from the (pre)configured SL-PRS resources pools

[0477] The WTRU may determine (e.g., at least) any of the following SL-PRS configurations from the set of (pre)configured SL-PRS configurations and/or the (pre)configured resource pools for SL-PRS for each of the anchor WTRUs in the sub-group:

• Time configuration: o For example, the WTRU may select the configuration with different number of symbols (e.g., 2 symbols per resource, 12 symbols per resource ), o For example, the WTRU may select a configuration with N1 number of OFDM symbols per resource based on (e.g., at least) any of the following conditions:

■ The number of determined Tx WTRU(s) in the sub-group is below a (pre)configured threshold,

■ The number of determined Rx WTRU(s) in the sub-group is below a (pre)configured threshold,

■ The total number of anchor WTRU(s) in the sub-group is below a (pre)configured threshold,

■ The distance of the anchor WTRU in the sub-group from the obstacle is above a (pre)configured threshold,

■ The uncertainty in location of the anchor WTRU in the sub-group is above a (pre)configured threshold,

■ The velocity of the anchor WTRU in the sub-group is above a (pre)configured threshold,

■ The uncertainty in the velocity of the anchor WTRU in the sub-group is above a (pre)configured threshold,

■ The uncertainty in obstacle location is above a (pre)configured threshold, ■ The velocity of the obstacle is above a (pre)configured threshold,

■ The QoS accuracy requirement for the obstacle location is above a (pre)configured threshold,

■ The QoS latency requirement for the obstacle location is above a (pre)configured threshold,

■ The energy available of the anchor WTRU is above a (pre)configured threshold, and/or

■ The allocated sub-group sensing duration is below a (pre)configured threshold; o The WTRU may select a configuration with N2 number of OFDM symbols otherwise. In one example, N1 may be greater than N2.

• Frequency configuration: o For example, the WTRU may select the configuration with varying allocated bandwidth (e.g., 100 RBs, 60 RBs), o For example, the target WTRU may select configurations with different comb shapes (e.g., comb 2, comb 12), o The WTRU may select a set of frequency configuration (e.g., with a bandwidth allocation of M1 (e.g., 100 MHz), Comb-N1 configurations) based on (e.g., at least) any of the following conditions:

■ The number of determined Tx WTRUs in the sub-group is below a (pre)configured threshold,

■ The number of determined Rx WTRUs in the sub-group is below a (pre)configured threshold,

■ The total number of anchor WTRUs in the sub-group is below a (pre)configured threshold,

■ The distance of the anchor WTRU in the sub-group from the obstacle is below a (pre)configured threshold,

■ The uncertainty in the location of the anchor WTRU in the sub-group is above a (pre)configured threshold,

■ The velocity of the anchor WTRU is above a (pre)configured threshold,

■ The uncertainty in the anchor velocity in the sub-group is above a (pre)configured threshold,

■ The uncertainty in obstacle location is above a (pre)configured threshold, ■ If the WTRUs in the sub-group is configured with time-based location estimation methods, the QoS accuracy requirement for obstacle location is above a (pre)configured threshold,

■ The allocated sub-group sensing duration is below a (pre)configured threshold; o The WTRU may select another set of frequency configurations (e.g., with a bandwidth allocation of M2 (e.g., 50 MHz), Comb-N2 configurations) otherwise;

• Type configuration (e.g., periodic, aperiodic, semi-persistent) o For example, the WTRU may select and/or determine a periodic configuration based on (e.g., at least) any of the following:

■ the obstacle velocity is above a (pre)configured threshold,

■ the uncertainty in obstacle velocity is above a (pre)configured threshold,

■ the total available sub-group sensing duration is above a (pre)configured threshold, and/or

■ the QoS requirement for sensing (e.g., accuracy, reliability) is above a (pre)configured threshold, o For example, the WTRU may select and/or determine aperiodic configuration if it satisfies at least one of the following:

■ the obstacle velocity is below a (pre)configured threshold,

■ the uncertainty in obstacle velocity is below a (pre)configured threshold, and/or

■ the total available sub-group sensing duration is below a (pre)configured threshold, o For example, the WTRU may select and/or determine a semi persistent configuration if it satisfies at least one of the following conditions:

■ the obstacle velocity is above a (pre)configured threshold,

■ the uncertainty in obstacle velocity is above a (pre)configured threshold, and/or

■ the total available sub-group sensing duration is below a (pre)configured threshold,

• Periodicity configuration (e.g., for periodic or semi-persistent configuration type) o For example, the WTRU may select and/or determine a configuration corresponding to a (e.g., different) SL-PRS resource periodicity (e.g., 1 slot, 5 slots), o The WTRU may select a configuration with a periodicity P1 in case of at least one of the following conditions: ■ The distance of the anchor WTRUs in the sub-group from the obstacle is below a (pre)configured threshold,

■ The uncertainty in obstacle location is above a (pre)configured threshold,

■ The allocated sub-group sensing duration is below a (pre)configured threshold, and/or

■ The QoS latency requirement for the obstacle location is above a (pre)configured threshold, o The WTRU may select a configuration with a periodicity P2 otherwise;

• Spatial configuration: o For example, the WTRU may select a spatial configuration (e.g., beamwidth, spatial coverage of the SRSp resources). o For example, the WTRU may determine to prioritize the SL-PRS resources for the WTRU in the sub-group such that the

■ The AoD of the selected SL-PRS resources are within the coverage area determined by the sub-group distance threshold, and/or

■ The difference in AoD of the selected SL-PRS resources and expected AoD to the obstacle below a (pre)configured threshold, o For example, the WTRU may determine to prioritize the SL-PRS resources with X1 degrees beamwidth based on (e.g., at least) any of the following conditions:

■ The distance of the WTRU in the sub-group from the obstacle is below a (pre)configured threshold,

■ the uncertainty in the location of the anchor WTRU in the sub-group is above a (pre)configured threshold, o The WTRU may determine a to prioritize SL-PRS resources with X2 degrees beamwidth otherwise, o For example, the WTRU may select a (sub)set of SL-PRS resources such that a coverage angle is C1 (e.g., 60 degrees) based on (e.g., at least) any of the following: ■ The distance of the WTRU in the sub-group from the obstacle is below a (pre)configured threshold,

■ the uncertainty in the location of the anchor WTRU in the sub-group is above a (pre)configured threshold, o The WTRU may determine a (sub)set of SL-PRS resources such that a coverage area C2 (e.g., 15 degrees) otherwise; and/or

• Measurement windows: o For example, the WTRU may determine the measurement windows from the set of (pre)configured SL-PRS configurations based on the selected transmission resources, o For example, the measurement window may include (e.g., at least) any of:

■ Start or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point),

■ Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds), and/or

■ Periodicity of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds).

[0478] In another example, the WTRU may determine these configurations and indicate the same to the sub-group of the anchor WTRU(s) for obstacle sensing.

[0479] In certain representative embodiments, a WTRU may activate the sub-group for bistatic sensing.

[0480] In one example, a WTRU may indicate (e.g., via SCI, SL-MAC-CE, PC5-RRC) the selected set of SL-PRS configurations to each WTRU (e.g., via unicast) via one or more indices (e.g., SL-PRS configuration ID, resource pool ID). The WTRU may indicate WTRU-specific SL-PRS transmission configurations to the subset of the sub-group WTRUs with the determined roles as transmitting WTRUs. The WTRU may indicate WTRU-specific reception configurations to the subset of the sub-group WTRUs with the determined roles as the receiving WTRUs.

[0481] In one example, the WTRU may (e.g., additionally) transmit (e.g., via groupcast) sub-group assistance information including (e.g., at least) any of the following:

• Group ID;

• Sub-group ID;

• Sub-group WTRU information: o Sub-group WTRU IDs, o Sub-group WTRU locations and/or their associated uncertainties range, o Sub-group WTRU velocities and/or their associated uncertainties range, o Sub-group WTRU roles (e.g., transmitting WTRU, receiving WTRU), and/or o Sub-group WTRU synchronization sources;

• Obstacle information: o Obstacle location and/or the associated uncertainties ranges, o Obstacle velocity and/or the associated uncertainties ranges, and/or o QoS requirements (e.g., accuracy, latency) for the obstacle location estimation;

• Sensing method (e.g., RTT);

• Measurement parameters (e.g., based on the configured positioning method (ToA, RSTD, AoA, AoD));

• Sub-group sensing window configurations (e.g., start time, stop time, duration); and/or

• Measurement reporting: o Reporting window (e.g., start time, stop time, duration), o Reporting contents (e.g., location, velocity, uncertainty ranges, measurements ), and/or o The WTRU I D(s) that may report the measurements and estimations.

[0482] In one example, the WTRU may determine to send both configuration indications and assistance information via unicast transmission.

[0483] In another example, the WTRU may determine to send the configuration indications via unicast as it may be unique to each WTRU and the assistance information via groupcast as they may contain common parameters.

[0484] In certain representative embodiments, a WTRU may receive a measurement report with obstacle location from the sub-group.

[0485] In one example, the WTRU may send (e.g. via groupcast) an indication (e.g., SCI indication) to the (sub-)group for initiating the transmission and measurement procedures.

[0486] In one example, the WTRU may receive a report from a (pre)configured reporting anchor WTRU in the sub-group. The measurement report may include (e.g., at least) any of: o Sub-group ID, o Obstacle location with the associated uncertainty range, o Obstacle velocity with the associated uncertainty range, o Measurements associated with the sub-group, and/or o Timestamp of the measurement corresponding to the obstacle location.

[0487] FIG. 18 is a signaling diagram illustrating signaling exchanges between a WTRU and anchor WTRUs for group and sub-group formation and procedures. Example procedures for group and sub-group- based sensing are illustrated in FIG. 18. At 1802, a (e.g., serving) WTRU 102 may send a sensing group indication to a set of anchor WTRUs, such as anchor WTRU 102a, anchor WTRU 102b, anchor WTRU 102c, and anchor WTRU 102d. For example, the sensing group indication may included a group sensing window duration. At 1804, an obstacle location of an obstacle 202 may be determined, such as between the WTRU 102 and the anchor WTRU 102b. At 1806, the WTRU 102 may send a sub-group formation indication to a sub-set of the anchor WTRUs, such as the anchor WTRU 102a, the anchor WTRU 102b, and the anchor WTRU 102c. At 1808, the WTRU 102 may send a sub-group transmission configuration identifier to the anchor WTRU 102a. At 1810, the WTRU 102 may send a sub-group reception configuration identifier to the anchor WTRUs 102b and 102c. At 1812, the anchor WTRU 102a may transmit (e.g., using the identified sub-group transmission configuration) a set of RSs, such as SL-PRSs, which may be received by the anchor WTRUs 102b and 102c (e.g., using the identified sub-group reception configuration). For example, the transmitted RSs may be send during a sub-group sensing window duration. At 1814, a measurement report may be received from the sub-group by the WTRU 102. For example, the measurement report may include an obstacle location determined using bistatic sensing according to the transmitted RSs at 1812.

[0488] Sub-group modification and deactivation

[0489] In certain representative embodiments, a WTRU may receive the anchor WTRU(s) location(s).

[0490] In one example, sub-group anchor WTRUs may be configured to report their locations to the WTRU (e.g., periodically). The location information may be used (e.g., required) to determine the validity of the subgroup as any WTRU mobility may change the sub-group properties.

[0491] In one example, a sub-group anchor WTRU may be configured to report its location to the WTRU upon detecting any change for two measurement occasions that is above a (pre)configured threshold.

[0492] In another example, a sub-group anchor WTRU may report its location and the associated uncertainty range periodically, such as with or in a measurement report.

[0493] In another example, a sub-group anchor WTRU may be configured to report its location and the associated uncertainty upon request from the WTRU.

[0494] In certain representative embodiments, a WTRU may receive a sub-group deactivation request from the sub-group anchor WTRU(s).

[0495] In one example, the WTRU may receive a request from the anchor WTRUs in the group for deactivation of the sub-group.

[0496] The WTRU may, for example, receive (e.g., at least) any of the following in the request: o The measurement value (e.g., RSRP, RTT, doppler shift), o The measurement value difference between N measurement occasions, o Anchor WTRU location and/or the associated uncertainty, and/or o Anchor WTRU velocity and/or the associated uncertainty.

[0497] In certain representative embodiments, a WTRU may determine to modify the sub-group. [0498] FIG. 19 is a system diagram illustrating sub-group modification due to obstacle movement. [0499] In one example, a (e.g., server) WTRU 102 may determine to modify the sub-group to form a modified sub-group 1902, as illustrated in FIG. 19. This modification may be triggered by (e.g., at least) any of the following conditions: o The reported RSRP measurement by the anchor WTRU corresponds to the obstacle being below a (pre)configured threshold, o The reported decrease in RSRP measurement corresponds to the obstacle between multiple measurement occasions is above a (pre)configured threshold, o The reported RTT corresponding to the obstacle is above a (pre)configured threshold, o The increase in the reported RTT corresponding to the obstacle in multiple measurement occasions is above a (pre)configured threshold, o The reported doppler shift measurement corresponding to the obstacle is above a (pre)configured threshold, o The reported difference between the measured doppler shift between multiple measurement occasions is above a (pre)configured threshold, o The anchor WTRU location difference between multiple measurement occasions is above a (pre)configured threshold, o The uncertainty in the anchor WTRU location is above a (pre)configured threshold, o The increase in uncertainty in anchor WTRU location in multiple measurement occasions is above a (pre)configured threshold, o The anchor WTRU velocity is above a (pre)configured threshold, o The uncertainty in anchor WTRU velocity is above a (pre)configured threshold, o The obstacle location difference between multiple measurement occasions in above a (pre)configured threshold, o The uncertainty in obstacle location is above a (pre)configured threshold, o The obstacle velocity difference in multiple measurement occasions is above a (pre)configured threshold, and/or o The remaining group sensing window duration is above a (pre)configured threshold.

[0500] In one example, a WTRU may request the location and/or the velocity with their associated uncertainty ranges of the sub-group anchor WTRUs.

[0501] In one example, the WTRU may determine to remove a sub-group anchor WTRU from the group- based on (e.g., at least) any of: o The distance between the obstacle and the anchor WTRU location is above a (pre)configured threshold, o The uncertainty in the anchor WTRU location is above a (pre)configured threshold, o The velocity of the anchor WTRU is above a (pre)configured threshold, and/or o The uncertainty in the velocity of the anchor WTRU is above a (pre)configured threshold.

[0502] In one example, the WTRU may determine to request the location and/or the velocity along with their associated uncertainty ranges of the group anchor WTRUs.

[0503] In one example, the WTRU may determine to add an anchor WTRU from the group to the sub- group-based on (e.g., at least) any of:

• The distance between the anchor WTRU and the obstacle is below a (pre)configured threshold,

• The uncertainty in the anchor WTRU location is below a (pre)configured threshold,

• The velocity of the anchor WTRU is below a (pre)configured threshold,

• The uncertainty in the velocity of the anchor WTRU is below a (pre)configured threshold, and/or

• The available energy of the anchor WTRU is above a (pre)configured threshold.

[0504] In one example, the WTRU may determine new WTRU roles (e.g., transmitting WTRUs, receiving WTRUs) for the anchor WTRUs in the modified sub-group.

[0505] In certain representative embodiments, a WTRU may activate the modified sub-group and send the modified assistance information.

[0506] In one example, a WTRU may determine to configure the modified sub-group with SL-PRS resources if the total number of WTRUs in the sub-group is above a (pre)configured threshold (e.g., M).

[0507] In one example, a WTRU may determine the SL-PRS transmission and reception configuration parameters from the set of (pre)configured SL-PRS configurations for the new sub-group anchor WTRUs.

[0508] In another example, a WTRU may either determine new or continue with previous configurations for the remaining anchor WTRUs in the sub-group. The WTRU may determine to continue with the previous configurations based on (e.g., at least) any of: o The difference in obstacle location in multiple measurement occasions is below a (pre)configured threshold, o The uncertainty in obstacle location is below a (pre)configured threshold, o The obstacle velocity is below a (pre)configured threshold, o The QoS requirements (e.g., latency, accuracy) between the old and the modified sub-groups is below a (pre)configured threshold, o The difference in distance between the removed anchor WTRUs and the added anchor WTRUs is below a (pre)configured threshold, o The difference in velocity between the removed anchor WTRUs and the added anchor WTRUs is below a (pre)configured threshold, and/or o The WTRU role between the old and the modified sub-group has not changed. [0509] The WTRU may determine and transmit modified assistance information to the modified sub-group.

The WTRU may indicate (e.g., at least) any of the following:

• Sub-group WTRU information: o Sub-group WTRU IDs, o Added sub-group IDs, o Removed sub-group IDs, o Sub-group WTRU locations and/or their associated uncertainties range, o Sub-group WTRU velocities and/or their associated uncertainties range, o Sub-group WTRU roles (e.g., transmitting WTRU, receiving WTRU), and/or o Sub-group WTRU synchronization sources;

• Sensing method (e.g., RTT);

• Sub-group sensing window configurations (e.g., start time, stop time, duration);

• Measurement reporting: o Reporting window (e.g., start time, stop time, duration), o Reporting contents (e.g., location, velocity, uncertainty ranges, measurements ), o The WTRU I D(s) that may report the measurements and estimations.

[0510] In certain representative embodiments, a WTRU may determine to deactivate the sub-group or group.

[0511] In one example, a WTRU may determine to deactivate the sensing group-based on (e.g., at least) any of the following conditions: o The total number of anchor WTRUs in the sub-group is below a (pre)configured threshold, o The distance (e.g., average distance) between the anchor WTRUs and the obstacle is above a (pre)configured threshold, o The expected RTT (e.g., average) between the Tx-Rx WTRU pairs in the sub-group is above a (pre)configured threshold, o The velocity of the WTRUs (e.g., average) between the anchor WTRUs in the sub-group is above a (pre)configured threshold, o The relative velocities between the WTRUs in the sub-group (e.g., with respect to a reference anchor WTRU within the sub-group) is above a (pre)configured threshold, and/or o The available sensing duration is below a (pre)configured threshold.

[0512] In one example, the WTRU may transmit (e.g., via groupcast) the indication to the sub-group of the anchor WTRUs to deactivate the sub-group.

[0513] Obstacle Reporting and Group Termination

[0514] In certain representative embodiments, a WTRU may send a measurement report to a target WTRU requesting sensing and/or the network.

[0515] I n one example, a WTRU may be configured to report a measurement report to a target WTRU that initiated the sensing request. In another example, the WTRU may be configured to report the measurement report to the network.

[0516] For example, a measurement report may include (e.g., at least) any of the following: o Obstacle locations and/or the associated uncertainty range, o Obstacle velocity and/or the associated uncertainty range, o Group ID, o The group anchor WTRUs IDs associated with the group ID, o Sub-group IDs, o The sub-group anchor WTRUs IDs associated with the sub-group ID, and/or o Timestamp of measurements associated with the obstacle location.

[0517] In certain representative embodiments, a WTRU may send an indication to the network of group termination.

[0518] In one example, the WTRU may determine to terminate the group-based on (e.g., at least) any of the following conditions: o The remaining total group sensing duration is below a (pre)configured threshold, o The remaining available energy (e.g., average) is below a (pre)configured threshold, and/or o The total number of anchor WTRUs in the group is below a (pre)configured threshold.

[0519] In one example, the WTRU may send an indication to the WTRUs in the group (e.g., via groupcast) of group termination.

[0520] In one example, the WTRU may send an indication to the network of group termination.

[0521] Sensing Mode Selection by the Anchor WTRU

[0522] In certain representative embodiments, a WTRU may be (pre)configured with one or more sets of SRSp configuration(s).

[0523] FIG. 20 is a system diagram illustrating mode selection based on bistatic and monostatic thresholds information (e.g., coverage areas). [0524] In one example, a WTRU 102 (e.g., anchor WTRU 904 in FIG. 20) may send a request to the network (e.g., LMF, gNB, entity that configures reference signals to the WTRU) for SRSp configuration, such as in the uplink physical channels (e.g., PUSCH or PUCCH), via higher layer signaling (e.g., MAC-CE or RRC), and/or via LPP messages.

[0525] In one example, the WTRU may receive one or more than one set of SRSp configuration(s) from the network for obstacle sensing.

[0526] In certain representative embodiments, a WTRU may be (pre)configured with the one or more sets of SL-PRS configurations.

[0527] In one example, the WTRU may send a request to the network (e.g., LMF, gNB, another WTRU, entity that configures reference signals to the WTRU) for SL-PRS configuration for sensing in the uplink physical channels, such as in the uplink physical channels (e.g., PUSCH or PUCCH), via higher layer signaling (e.g., MAC-CE or RRC), and/or via LPP messages.

[0528] In one example, the WTRU may receive the one or more sets of SL-PRS configuration(s) from the network (e.g., LMF, gNB) including at least the time, frequency, periodicity, and spatial configurations. In one example, in case of multiple configuration sets, the WTRU may also receive an index (e.g., SL-PRS configuration ID) associated with each configuration.

[0529] As used herein, a target WTRU, such as in FIG. 20 may be a TRP or gNB. The WTRU may receive PRS configurations from the network for bi-static sensing. A “target WTRU” may be used interchangeably with “TRP” or “gNB” in the examples described herein.

[0530] Discovery Procedure

[0531] In certain representative embodiments, a WTRU may receive a discovery message from a target WTRU.

[0532] In one example, a WTRU may be (pre)configured by the network with one or more resource pools. Each resource pool may include resources for receiving (e.g., SCI, data) discovery messages from other WTRUs in the vicinity.

[0533] In another example, a WTRU may receive a resource pool including f the resources for receiving discovery messages from the network (e.g., in SIB messages).

[0534] In one example, if the WTRU is (pre)configured with the resource pools for discovery messages, the WTRU may monitor and receive the discovery message from another WTRU in the vicinity.

[0535] In another example, the WTRU may receive a discovery message from another WTRU in the vicinity, such as via PC5 interface or any other interface (e.g., RRC) allowing connection between the WTRUs.

[0536] In certain representative embodiments, a WTRU may receive the assistance information and the conditions in the discovery message. [0537] In one example, a WTRU may receive one or more combinations of the target WTRU information, the obstacle’s information and the requirements including (e.g., at least) any of:

• Target WTRU information: o Target WTRU ID (e.g., RNTI), or any other IDs that are used to identify the target WTRU, o Target WTRU location and/or the associated uncertainty range, o Target WTRU coverage information (e.g., in coverage, cell ID) o Target WTRU sensing zone (e.g., maximum monostatic RTT threshold), o (Maximum) transmission power, o Synchronization source information (e.g., time/frequency/phase synchronization), and/or o Supported frequency range (e.g., FR1 , FR2) and/or SCS and/or (maximum) bandwidth for SL-PRS;

• Required WTRU capabilities: o Capability to estimate its location, o Capability to perform sidelink measurements (e.g., time, angle, frequency, frequency shift), o Capability to perform a specific positioning method (e.g., RTT), o Capability to obtain obstacle location coordinates from the measurements, o Capability to report its location to the network, WTRU (e.g., server WTRU), o Capability to report the obstacle(s)’ location to the network, WTRU (e.g., server WTRU), o Capability to report the measurements to the network, WTRU (e.g., server WTRU), o Sensing duration (e.g., start time, duration, stop time), o Required time resolution threshold for time related positioning methods (e.g., RTT, TDoA) threshold, o Required angle resolution threshold for angle related positioning methods (e.g., AoD, AoA), o Required velocity resolution threshold for velocity related positioning methods, and/or o Required minimum energy threshold.

[0538] In one example, the WTRU may (e.g., also) receive a request to transmit the assistance information to the network including any of anchor WTRU information and/or anchor WTRU capability information.

[0539] In certain representative embodiments, a WTRU may respond to a discovery message. [0540] In one example, a WTRU may determine to respond to a discovery message based on (e.g., at least) any of the following conditions: o The distance between the WTRU and the obstacle is below a (pre)configured distance threshold, o The uncertainty in the obstacle location is above a (pre)configured threshold, o The velocity of the obstacle is above a (pre)configured threshold, o The uncertainty in the obstacle velocity is above a (pre)configured threshold, o The transmission power of the target WTRU is above a (pre)configured threshold, o The distance between the target WTRU and the obstacle is below a (pre)configured threshold, o The priority to other RS (e.g., PDSCH) during the sensing duration is below a (pre)configured threshold, o The clock synchronization offset between the WTRU and the target WTRU is known to the WTRU, o Source of clock synchronization is known (e.g., GNSS, network, peer WTRU), o The WTRU supports the indicated frequency range of the target WTRU for sensing, o The energy requirement for sensing is above a (pre)configured threshold, o The WTRU supports the required measurement capabilities (e.g., capability to locate itself, capability to perform configured measurements (e.g., RTT), capability to meet the time/angle/velocity resolution requirements), o The WTRU supports the required processing capabilities (e.g., capability required to perform FFT computation of the required time and/or frequency samples), and/or o The WTRU supports the required reporting capabilities (e.g., capability to report the obstacle’s location/measurements to the indicated entity (e.g., network)).

[0541] In one example, the WTRU may determine to include, in its response, an acceptance (e.g., “Yes” or ACK) or denial (e.g., “No” or NACK) for the request in the discovery message.

[0542] In one example, the WTRU may (e.g., also) determine to transmit the assistance information to the target WTRU in the response to the discovery message. The WTRU may transmit (e.g., at least) any of the following:

• Anchor WTRU information: o Anchor WTRU ID (e.g., RNTI), o Anchor WTRU location and/or its uncertainty range, o Anchor WTRU velocity and/or its uncertainty range, o Anchor WTRU coverage information (e.g., in coverage, out of coverage, cell ID), and/or o Anchor WTRU duplexing information (e.g., full duplex WTRU); and/or

Anchor WTRU capability information: o (Maximum) transmit power, o Supported sensing methods (e.g., RTT), o Supported measurements (e.g., ToA, RSTD, AoA), o Supported maximum number of obstacles, o Available sensing start time and duration, and/or o Available WTRU energy.

[0543] Bistatic Sensing Request

[0544] In certain representative embodiments, a WTRU may receive a bistatic sensing request from a target WTRU.

[0545] In one example, a WTRU may receive a bistatic sensing request from a target WTRU and/or network, such as through one of the sidelink signals and/or Uu specific signals (e.g., SCI, SL-MAC-CE, PC5- RRC messages, DCI, MAC-CE, RRC, and/or LPP).

[0546] In one example, the request may include an indication of the amount resources that may be transmitted. The WTRU may receive (e.g., at least) any of the following:

• Bistatic RTT thresholds (e.g., threshold_min and thresholdjnax);

• Measurement window configurations: o Start or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point), o Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds), and/or o Periodicity of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds);

• Sensing window configurations: o Start or end time of the window (e.g., in terms of symbol index, slot index, frame index, absolute time, relative time with respect to a reference point), o Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds), and/or o For example, the sensing window may indicate the time that the anchor WTRU(s) may need to reserve for sensing;

• QoS requirement for obstacle location (e.g., accuracy, latency, reliability);

• SL-PRS transmission bandwidth (e.g., in terms of RBs, Hz);

• Total energy for sensing (e.g., in terms of joules); and/or

• Transmission power level (e.g., indication of pathloss RS for determination of power, relative difference in power with respect to a pathloss RS or transmission power). [0547] In certain representative embodiments, a WTRU may receive bistatic RTT threshold information from a target WTRU and/or network.

[0548] In one example, a WTRU may receive bistatic RTT thresholds (e.g., thresholdjnax, threshold_min) from the network.

[0549] In another example, a WTRU may receive the bistatic RTT thresholds (e.g., thresholdjnax, threshold_min) from a target WTRU.

[0550] In certain representative embodiments, a WTRU may autonomously determine the bistatic RTT thresholds.

[0551] In certain representative embodiments, a WTRU may implicitly determine the bistatic thresholds based on the assistance information. For example, the WTRU may determine a threshold nax (e.g., Y1 ms) based on (e.g., at least) any of the following conditions:

• Target WTRU’s maximum transmission power is above a (pre)configured threshold,

• The QoS accuracy requirement is below a (pre)configured threshold,

• The QoS reliability requirement is below a (pre)configured threshold,

• The obstacle velocity is below a (pre)configured threshold,

• The uncertainty in the WTRU location is below a (pre)configured threshold,

• The uncertainty in the target WTRU location is below a (pre)configured threshold, and/or

• The distance between the WTRU and the target WTRU is above a (pre)configured threshold

[0552] For example, the WTRU may determine another thresholdjnax (e.g., Y2 ms) otherwise.

[0553] For example, the WTRU may determine a threshold_mi n (e.g., Z1 ms) if the configured bandwidth is below a (pre)configure threshold and another threshold (e.g., Z2 ms) otherwise.

[0554] In another example, the WTRU may (e.g., also) be configured with one or more sets of thresholdjnax and threshold jnin bistatic thresholds (e.g., via tables and/or equations) dependent on various values of the above-mentioned parameters. The WTRU may then, based on the determined values of one or more of the parameters, select a suitable threshold_min and thresholdjnax from the (pre)configured set. [0555] In certain representative embodiments, a WTRU may receive a monostatic RTT threshold from the network.

[0556] In one example, the monostatic threshold may determine a coverage area where the WTRU may determine to perform monostatic sensing (e.g., independently or in addition to the bistatic sensing).

[0557] In certain representative embodiments, a WTRU may autonomously determine the monostatic RTT threshold.

[0558] In certain representative embodiments, a WTRU may determine the monostatic RTT threshold (e.g., X ms) autonomously based on (e.g., at least one) any of the following conditions:

• The WTRU velocity is above a (pre)configured threshold, o For example, the WTRU with X m/s velocity may approach the obstacle more quickly and hence may benefit from sensing the obstacle with above threshold coverage area compared,

• The uncertainty in the WTRU location is above a (pre)configured threshold, o For example, an above threshold uncertainty in the WTRU location may mean that the obstacle already within a threshold distance of the WTRU may not be detected as so,

• The transmission power of the WTRU is above a (pre)configured threshold, o For example, the transmission power determines the absolute maximum monostatic sensing coverage area. Hence, the large available transmission power may be associated with a large monostatic RTT threshold, and/or o For example, X dBm of transmission power may be associated with Y ms of monostatic RTT threshold,

• The WTRUs energy availability is above a (pre)configured threshold, o For example, the energy availability of the target WTRU may determine the transmission power and hence may be associated with the monostatic RTT threshold, and/or o For example, a X Joules of energy availability may be associated with Y ms of monostatic RTT threshold,

• The QoS accuracy requirement for locating the obstacle is below a (pre)configured threshold, o For example, locating an obstacle with large distance from the WTRU may result in low accuracy due to the signal attenuation, channel fading, blockages Hence, the WTRU may determine a large sensing coverage area if the accuracy requirement is below a threshold, and/or o For example, an accuracy requirement (e.g., X m horizontal, Y m vertical accuracy) may be associated with Z ms of RTT threshold,

• The QoS reliability requirement for locating the obstacle is below a (pre)configured threshold, o For example, locating an obstacle with large distance from the WTRU may result in low reliability due to the signal attenuation, channel fading, blockages,

• The transmission power of the target WTRU is below a (pre)configured threshold, o For example, the WTRU may determine a monostatic RTT threshold if the transmission power of the target WTRU and hence the possible bistatic coverage area is below a threshold. This determination may allow the WTRU locate obstacles that may be missed through bistatic sensing, and/or o For example, X dBm of target WTRU transmission power may be associated with Y ms of RTT threshold,

The uncertainty of the target WTRU location is above a (pre)configured threshold, o For example, the uncertainty in the target WTRU location may increase the error in bistatic sensing. Hence, the WTRU may determine monostatic sensing coverage area to increase the accuracy of obstacle location,

• The obstacle velocity is above a (pre)configured threshold, o For example, a high velocity obstacle may approach the WTRU quickly and may pose potential safety risks. Hence, the WTRU may determine a large monostatic RTT threshold for obstacles with above threshold velocity, and/or o For example, X m/s obstacle velocity may be associated with Y ms of monostatic RTT threshold,

• The obstacle priority is above a (pre)configured threshold, o For example, if the obstacle priority to the WTRU is determined to be above a threshold, the WTRU may determine to increase the sensing coverage area, and/or o For example, a high priority obstacle may be associated with X ms of monostatic RTT threshold, and a low priority obstacle may be associated with Y ms of monostatic RTT threshold, where X may be greater than Y, and/or

• The uncertainty in the obstacle location is above a (pre)configured threshold, o For example, if the uncertainty in the obstacle location is above the threshold, the WTRU may not accurately know if the obstacle is in the coverage area or not. Hence the WTRU may determine an above threshold monostatic RTT threshold For example, for safety.

[0559] In one example, the WTRU may determine another monostatic RTT threshold (e.g., Y ms) if the above conditions are not satisfied.

[0560] In another example, the WTRU may also be configured with one or more sets of monostatic RTT thresholds (e.g., via tables and/or equations) which may be dependent on various values of one or more of the above-mentioned parameters. The WTRU may then, based on the determined values of the parameters, select a suitable monostatic RTT threshold from the (pre)configured set.

[0561] Sensing Mode Selection

[0562] In certain representative embodiments, a WTRU may determine to start sensing for obstacle location estimation.

[0563] In one example, a WTRU may determine to perform sensing for obstacle location estimation. The trigger conditions for this determination may be (e.g., at least) any of the following:

• The WTRU receives a discovery message for sensing from other entities (e.g., target WTRU),

• The WTRU receives a request for sensing from other entities (e.g., target WTRU),

• The WTRU satisfies the conditions for obstacle detection,

• The distance between the WTRU and the obstacle is below a (pre)configured threshold, • The obstacle velocity is above a (pre)configured threshold,

• The WTRU receives configurations from the network (e.g., LMF, gNB) or peer WTRU (e.g., WTRU with LMF capability) for both monostatic sensing (e.g., SRSp configurations) and bistatic sensing (e.g., SL-PRS, PRS or SRSp), and/or

• The determined priority of the obstacle is above a (pre)configured threshold.

[0564] FIG. 21 is a flow diagram illustrating a sensing mode selection procedure for monostatic and bistatic sensing. At 2102, a WTRU 102 may receive SRSp and SL-PRS configurations from the network. At 2104, the WTRU 102 may send a discovery message which includes information indicating an obstacle location. At 2106, the WTRU 102 may receive a discovery response and determine if the distance to the obstacle is less than a threshold. If not, the WTRU 102 may determine not to perform sensing at 2108. If the distance to the obstacle is less than the threshold, the WTRU 102 may determine if the expected monostatic RTT is less than a threshold at 2110. If the expected monostatic RTT is less than the threshold, the WTRU 102 may determine to perform monostatic sensing at 2112. If not, the WTRU 102 may determine if the expected bistatic RTT is within a threshold at 2114. If the expected bistatic RTT is not within the threshold, the WTRU may determine not to perform sensing at 2108. If the expected bistatic RTT is within the threshold, the WTRU 102 may determine to perform bistatic sensing at 2116.

[0565] In certain representative embodiments, a WTRU may determine to perform bistatic sensing.

[0566] In one example, a WTRU may determine to perform bistatic sensing and assist a target WTRU based on (e.g., at least) any of the following conditions:

• The expected bistatic RTT associated with the WTRU and the target WTRU is below a (pre)configured bistatic thresholdjnax,

• The expected bistatic RTT associated with the WTRU and the target WTRU is above a (pre)configured bistatic threshold_min,

• The expected monostatic RTT associated with the WTRU is above a (pre)configured monostatic threshold,

• The indication received by the network or peer WTRU, indicating to perform bistatic sensing,

• The WTRU is not configured with parameters for monostatic sensing (e.g., SRSp), or the WTRU is not configured with a monostatic sensing method by the network or peer WTRU,

• The monostatic sensing is configured as the default sensing method and the WTRU falls back to monostatic sensing when conditions to perform bi-static sensing are not satisfied,

• The uncertainty in target WTRU location is below a (pre)configured threshold,

• The target WTRU velocity is below a (pre)configured threshold,

• The relative velocity between the WTRU and the target WTRU is below a (pre)configured threshold,

• The clock synchronization offset between the WTRU and the target WTRU is known to the WTRU, • The available sensing duration is below the (pre)configured threshold (e.g., defined by sensing window configurations), o For example, the WTRU may determine to perform bistatic sensing if its priority to other RS during the indicated sensing window is below a (pre)configured threshold, and/or o For example, the WTRU may determine to do bistatic sensing its priority to sensing the obstacle is above a (pre)configured threshold,

• The QoS accuracy requirement for sensing is below a (pre)configured threshold, o For example, the WTRU may determine to perform sensing if the QoS accuracy requirement (e.g., indicated by the target WTRU) is below a (pre)configured threshold, and/or o For example, the WTRU may also determine this threshold based on location, obstacle location, its capabilities (e.g., sensing time/angle and/or velocity resolution),

• The total target WTRU’s bandwidth is above a (pre)configured threshold, o For example, the below threshold bandwidth may reduce the resolution and hence the accuracy of time-based sensing methods, and/or

• The total target WTRU’s available energy for sensing is above a (pre)configured threshold, o For example, the target WTRU’s energy may determine the transmission power and hence may affect the accuracy of sensing. The WTRU may receive the SRSp resources with high SNR/RSRP if the target WTRU’s available energy is above the threshold.

[0567] In one example, the WTRU may determine not to do accept the bistatic sensing request if the above conditions are not satisfied.

[0568] In certain representative embodiments, a WTRU may determine to perform monostatic sensing.

[0569] In one example, the WTRU may determine to perform monostatic sensing based on (e.g., at least) any of the following conditions:

• The expected monostatic RTT is below a (pre)configured monostatic RTT threshold,

• The WTRU can perform full duplex transmission and reception,

• The uncertainty in WTRU location is below a (pre)configured threshold, o For example, an above threshold uncertainty in the WTRU location may reduce the accuracy of the obstacle location estimation,

• The obstacle velocity is above a (pre)configured threshold,

• The indication received by the network or peer WTRU, indicating to perform monostatic sensing,

• The WTRU is not configured with parameters for bi-static sensing (e.g., PRS), or the WTRU is not configured with a bi-static sensing method by the network or peer WTRU,

• The bistatic sensing is configured as the default sensing method and the WTRU falls back to bistatic sensing when conditions to perform monostatic sensing are not satisfied, • The uncertainty in the target WTRU location is above a (pre)configured threshold,

• The target WTRU’s transmission power is below a (pre)configured threshold,

• The target WTRU’s available energy is below a (pre)configured threshold,

• The WTRU’s available sensing duration is above a (pre)configured threshold,

• The QoS latency requirement for sensing the obstacle is above a (pre)configured threshold, o For example, with monostatic sensing, the WTRU may transmit, measure and estimate the location of the obstacle. It may avoid the additional signalling and hence the latency required between multiple entities (e.g., collection of measurement data, measurement reporting) which may be required in bistatic sensing, and/or

• The WTRU’s available bandwidth for sensing is above a (pre)configured threshold,

[0570] In one example, the WTRU may determine not to perform monostatic sensing if the above conditions are not satisfied.

[0571] In certain representative embodiments, a WTRU may determine not to perform bistatic or monostatic sensing.

[0572] In one example, a WTRU may determine to not perform either monostatic or bistatic sensing based on (e.g., at least) any of the following conditions:

• The expected bistatic RTT associated with the WTRU and the target WTRU is above a (pre)configured bistatic thresholdjnax,

• The expected bistatic RTT associated with the WTRU and the target WTRU is below a (pre)configured bistatic threshold_min,

• The distance between the target WTRU and the obstacle is above a (pre)configured threshold,

• The distance between the WTRU and the target WTRU is above a (pre)configured threshold,

• The WTRU’s transmission power is below a (pre)configured threshold,

• The WTRU’s available sensing duration is below a (pre)configured threshold,

• The target WTRU’s available sensing duration is below a (pre)configured threshold,

• The WTRU’s available bandwidth for sensing is below a (pre)configured threshold,

• The target WTRU’s available bandwidth for sensing is below a (pre)configured threshold,

• The obstacle priority is below a (pre)configured threshold,

• The WTRU’s available energy for sensing is below a (pre)configured threshold, • The target WTRU’s available energy for sensing is below a (pre)configured threshold,

• The uncertainty in the WTRU’s location is above a (pre)configured threshold,

• The uncertainty in the target WTRU’s location is above a (pre)configured threshold, and/or

• The clock synchronization offset between the WTRU and the target WTRU is known to the WTRU. [0573] In certain representative embodiments, a WTRU may respond to the bistatic sensing request. [0574] In one example, a WTRU may respond to the bistatic sensing request, such as via sidelink specific signals (e.g., SCI, SL-MAC-CE, and/or PC5-RRC messages).

[0575] In one example, the WTRU may accept the bistatic sensing request and respond to accept the request (e.g., “Yes” or ACK) for bistatic sensing.

[0576] In one example, the WTRU may determine to perform monostatic sensing for obstacle location and may respond to decline the request (e.g., “No” or NACK) to the bistatic sensing request.

[0577] In one example, the WTRU may determine not to perform any sensing and may respond to decline (e.g., “No” or NACK) the bistatic sensing request.

[0578] SL-PRS/SRSp Configuration

[0579] In certain representative embodiments, a WTRU may configure the resources for transmission and/or reception in case it determines to either perform bistatic or monostatic sensing.

[0580] In certain representative embodiments, a WTRU may receive the configurations for bistatic sensing.

[0581] In one example, in case the WTRU determines and responds to the request to perform bistatic sensing, the WTRU may receive (e.g., at least) any of the following from the target WTRU:

• Measurement window i ndication/config uration: o In one example, the WTRU may receive an indication to activate the measurement window that may have either been (pre)configured to the WTRU or indicated during the bistatic sensing request, o In another example, the WTRU may receive the configurations for a new measurement window from the target WTRU, and/or o In another example, the WTRU may receive an indication of the resource pool that may contain the measurement window to be activated if the WTRU may (pre)configured with the SL-PRS resource pool;

• Assisting measurement information that may assist the WTRU: o For example, the WTRU may receive the configured SL-PRS resource ID(s), SL-PRS resource set I D(s) that may be likely to be reflected from the obstacle, o For example, the WTRU may receive any combination of the number of symbols/slots, bandwidth, comb values, periodicity, o For example, the WTRU may receive the expected RTT range (e.g., in terms of symbol indices, slot indices, frame indices, absolute time, relative time with respect to a reference point (e.g., start time of measurement window)) when it may receive reflections from the obstacle, o For example, the WTRU may receive the expected AoA range (e.g., with respect to a absolute orientation (e.g., geographical north), target WTRU orientation, anchor WTRU orientation) relevant to the obstacle’s (coarse) location, and/or o For example, the WTRU may receive the type of transmission (e.g., periodic, semi- persistent, aperiodic) and may also indicate the periodicity of the transmission (if relevant); and/or

• Assisting reporting information characterized one of the following parameters: o For example, the WTRU may receive the reporting time (e.g., in terms of symbol indices, slot indices, frame indices, absolute time, relative time with respect to a reference point (e.g., end of measurement window)), o For example, the WTRU may receive the reporting frequency (e.g., periodic) and/or its periodicity along with the reporting trigger, and/or o For example, the WTRU may receive the priority associated with reporting the measurements and/or estimations.

[0582] In certain representative embodiments, a WTRU may activate the measurement window and/or the configurations for bistatic sensing.

[0583] In one example, a WTRU may receive an indication (e.g., via SCI, SL-MAC CE) from the target WTRU to activate the measurement window configurations.

[0584] In one example, a WTRU may receive the transmitted SL-PRS resources and perform the configured measurements.

[0585] In one example, a WTRU may determine the obstacle location and/or velocity based on the measurements and other assistance information.

[0586] In one example, a WTRU may report (e.g., at least) any of the following to a target WTRU:

• Obstacle location and/or the associated uncertainty range,

• Obstacle velocity and/or the associated uncertainty range,

• The measurements associated with the obstacle (e.g., RTT, AoA, RSRP ),

• The uncertainties in the measurements associated with the obstacle, and/or

• Timestamp associated with the obstacle location and/or velocity measurements.

[0587] In certain representative embodiments, a WTRU may determine the SRSp configurations for monostatic sensing. [0588] In one example, if a WTRU determines to perform monostatic sensing, it may determine the SRSp configurations including (e.g., at least) any of the following:

• Time configuration: o For example, the WTRU may select the configuration with different number of symbols (e.g., 2 symbols per resource, 12 symbols per resource), o For example, the WTRU may select/determine a configuration with N1 number of OFDM symbols per resource in case of at least one of the following conditions:

■ The distance between the WTRU and the obstacle is below a (pre)configured threshold,

■ The monostatic RTT threshold is below a (pre)configured threshold,

■ The energy available of the WTRU is above a (pre)configured threshold,

■ The sensing duration available to the WTRUs is below a (pre)configured threshold,

■ The velocity of the obstacle is above a (pre)configured threshold,

■ The uncertainty in obstacle location is above a (pre)configured threshold,

■ The uncertainty in WTRU location is above a (pre)configured threshold, and/or

■ The obstacle priority to the WTRU is above a (pre)configured threshold, o The WTRU may select the configuration N2 number of OFDM symbols otherwise. In one example, N1 may be greater than N2;

• Frequency configuration: o For example, the WTRU may select the configuration with varying allocated bandwidth (e.g., 100 RBs, 60 RBs), o For example, the WTRU may select configurations with different comb shapes (e.g., comb 2, comb 12), o The WTRU may select/determine a one set of frequency configuration (e.g., with a bandwidth allocation of M1 (e.g., 100 MHz), Comb-N1 configurations) in case of (e.g., at least) any of the following conditions:

■ The monostatic RTT threshold is below a (pre)configured threshold,

■ The QoS latency requirement is above a (pre)configured threshold, ■ The energy available to WTRU is above a (pre)configured threshold,

■ The sensing duration available to the WTRU is below a (pre)configured threshold,

■ The velocity of the obstacle is above a (pre)configured threshold,

■ The obstacle priority to the WTRU is above a (pre)configured threshold,

■ The uncertainty in WTRU location is above a (pre)configured threshold, o The WTRU may select another set of frequency configuration (e.g., with a bandwidth allocation of M2 (e.g., 50 MHz), Comb-N2 configurations) otherwise;

• Periodicity configuration: o For example, the WTRU may select the configuration corresponding to different SRSp resource periodicity (e.g., 1 slot, 5 slots), o The WTRU may select a configuration with a periodicity P1 in case of at least one of the following conditions:

■ The monostatic RTT threshold is below a (pre)configured threshold,

■ The velocity of the obstacle is above a (pre)configured threshold,

■ The sensing duration allocated is below a (pre)configured threshold,

■ The QoS latency requirement is above a (pre)configured threshold,

■ The available sensing energy is above a (pre)configured threshold, and/or

■ The obstacle priority to the WTRU is above a (pre)configured threshold, o The WTRU may select a configuration with a periodicity P2 otherwise; and/or

• Spatial configuration: o For example, the WTRU may select the spatial configurations (e.g., AoDs, beamwidth, spatial coverage of the SRSp resources), o For example, the WTRU may determine to prioritize the SRSp resources such that the o The difference in AoD of the selected SRSp resources and expected AoD/AoA to the obstacle is below a (pre)configured threshold, o For example, the WTRU may determine to prioritize the SRSp resources with X1 degrees beamwidth based on (e.g., at least) any of the following conditions:

■ the distance between the WTRU and the obstacle is below (pre)configured threshold,

■ the uncertainty in WTRU location is above a (pre)configured threshold, o The WTRU may determine to prioritize another beamwidth X2 degrees if the above- mentioned conditions are not fulfilled, o For example, the WTRU may select/determine a (sub)set of SRSp resources such that the coverage angle C1 degrees (e.g., 60 degrees) in case of at least one of the following:

■ the uncertainty in WTRU location is above a (pre)configured threshold, o The WTRU may determine another coverage angle C2 degrees (e.g., 15 degrees) otherwise.

[0589] In another example, the WTRU may determine the SRSp resources from a set of (pre)configured SRSp resources based on any of the above-mentioned conditions.

[0590] In another example, the WTRU may request and receive one or more SRSp configurations for monostatic sensing (e.g., explicitly) from the network.

[0591] In certain representative embodiments, a WTRU may transmit, receive, and measure the configured SRSp resources for monostatic sensing.

[0592] In one example, the WTRU may transmit the configured SRSp resources at the indicated time and frequency resources and may receive the reflected resources back from the obstacle. The WTRU may measure any of the monostatic RTT, RSRP, doppler frequency and the like from the received resources. The WTRU may use these measurements to locate the obstacle.

[0593] In one example, the WTRU may report (e.g., at least) any of the following to the network:

• Obstacle location and/or the associated uncertainty range,

• Obstacle velocity and/or the associated uncertainty range,

• The measurements associated with the obstacle (e.g., RTT, AoA, RSRP),

• The uncertainties in the measurements associated with the obstacle, and/or

[0594] The WTRU may send a measurement report, such as via lower or higher layer signals (e.g., UCI, MAC CE, RRC, LPP, and/or SLPP) to the network and/or peer WTRU.

[0595] In a representative embodiment, a (e.g., anchor) WTRU may receive DL-PRS and SRSp configuration information from the network (e.g., for sensing). The DL-PRS and/or SRSp configurations may include any of obstacle location, TRP locations, bistatic time thresholds (e.g., threshold_min, thresholdjnax) and/or a monostatic threshold. The WTRU may receive a request for bistatic sensing from the network (e.g., with a measurement window). For example, the WTRU may determine to perform bistatic sensing and accept the bistatic sensing request (e.g., respond “Yes”) based on any of the expected bistatic RTT is above threshold_min (e.g., outside of the ambiguity range) and/or below thresholdjnax (e.g., below the maximum range), and/or the expected monostatic RTT is above the monostatic RTT threshold. For example, the WTRU may determine to perform monostatic sensing and decline the bistatic sensing request (e.g., respond “No”) based on the expected monostatic RTT being below the monostatic threshold. For example, the WTRU may determine to not perform any (e.g., bistatic and monostatic) sensing and decline the bistatic sensing request (e.g., respond “No”) based on the expected bistatic RTT and monostatic RTT being above the thresholdjnax and monostatic threshold, respectively. The WTRU may configure the resources for transmission and/or reception. If the WTRU’s response is “Yes”, the WTRU may activate the measurement window and receives the DL-PRS(s) in the DL-PRS resources for bistatic sensing. If the WTRU’s response is “No” and it determines to perform monostatic sensing, the WTRU may configure the SRSp resources for monostatic sensing, and transmit and receive SRSp(s) in the SRSp resources.

[0596] Bistatic Obstacle Prioritization for Multiple Bistatic Sensing Requests

[0597] In certain representative embodiments, a WTRU may be (pre)configured with the one or more sets of SL-PRS configurations.

[0598] FIG. 22 is a system diagram illustrating a request from multiple target WTRUs for bistatic sensing and priority allocation.

[0599] In one example, a WTRU 102 (e.g., anchor WTRU 904 FIG. 22) may send a request to the network (e.g., LMF, gNB, another WTRU, entity that configures reference signals to the WTRU) for SL-PRS configurations (e.g., for sensing), such as in the uplink physical channels (e.g., PUSCH and/or PUCCH), via higher layer signaling (e.g., MAC-CE and/or RRC), or via LPP messages.

[0600] In one example, a WTRU may receive one or more sets of SL-PRS configurations from the network (e.g., LMF, gNB) including any of time, frequency, periodicity, and/or spatial configurations. In one example, in the case of multiple configuration sets, the target WTRU may also receive an index (e.g., SL-PRS configuration ID) associated with each configuration or set.

[0601] Discovery Procedure

[0602] In certain representative embodiments, a WTRU may receive a discovery message from one or more target WTRU(s).

[0603] In one example, a WTRU may be (pre)configured by the network with one or more resource pools including the resources (e.g., SCI, data) for receiving the discovery message from other WTRU(s) (e.g., Target WTRUs in Figure 21) in the vicinity.

[0604] In another example, a WTRU may receive a resource pool including the resources for receiving the discovery messages from the network (e.g., in SIB messages).

[0605] In one example, if the WTRU is (pre)configured with the resource pools for discovery messages, the WTRU may monitor and receive the discovery messages from multiple target WTRU(s) in the vicinity. [0606] In another example, a WTRU may receive a discovery message from multiple target WTRU(s) in the vicinity, such as via PC5 interface or any other interface allowing connection between WTRUs.

[0607] In certain representative embodiments, a WTRU may receive the assistance information and the conditions in the discovery message.

[0608] In one example, the WTRU may receive any of the target WTRU information, the obstacle’s information and/or the requirements, such as (e.g., at least) any of the following:

• Target WTRU information: o Target WTRU ID (e.g., RNTI), or any other IDs that are used to identify the target WTRU, o Target WTRU location and/or the associated uncertainty range, o Target WTRU coverage information (e.g., in coverage, cell ID), o Target WTRU sensing zone (e.g., maximum monostatic RTT threshold), o (Maximum) transmission power, o Synchronization source information (e.g., time/frequency/phase synchronization), and/or o Supported frequency range (e.g., FR1 , FR2) and/or SCS and/or (maximum) bandwidth for SL-PRS;

[0609] In one example, the WTRU may also receive a request to transmit assistance information to the network, such as any of anchor WTRU information, and/or anchor WTRU capability information.

[0610] In certain representative embodiments, a WTRU may respond to a discovery message.

[0611] In one example, the WTRU may determine to respond to the discovery message based on (e.g., at least) any of the following conditions: o The distance between the WTRU and the obstacle is below a (pre)configured distance threshold, o The uncertainty in the obstacle location is above a (pre)configured threshold, o The velocity of the obstacle is above a (pre)configured threshold, o The uncertainty in the obstacle velocity is above a (pre)configured threshold, o The transmission power of the target WTRU is above a (pre)configured threshold, o The distance between the target WTRU and the obstacle is below a (pre)configured threshold, o The priority to other RS (e.g., PDSCH) during the sensing duration is below a (pre)configured threshold, o The clock synchronization offset between the WTRU and the target WTRU is known to the WTRU, o Source of clock synchronization is known (e.g., GNSS, network, peer WTRU) o The WTRU supports the indicated frequency range of the target WTRU for sensing, o The energy requirement for sensing is above a (pre)configured threshold, o The WTRU supports the required measurement capabilities (e.g., capability to locate itself, capability to perform configured measurements (e.g., RTT), capability to meet the time/angle/velocity resolution requirements), o The WTRU supports the required processing capabilities (e.g., capability required to perform FFT computation of the required time and/or frequency samples), and/or o The WTRU supports the required reporting capabilities (e.g., capability to report the obstacle’s location/measurements to the indicated entity (e.g., network)).

[0612] In one example, the WTRU may determine to include, in its response, an acceptance (e.g., “Yes” or ACK) or denial (e.g., “No” or NACK) for the request in the discovery message.

[0613] In one example, the WTRU may (e.g., also) determine to transmit the assistance information to the target WTRU in the response to the discovery message. The WTRU may transmit (e.g., at least) any of the following:

• Anchor WTRU information: o Anchor WTRU ID (e.g., RNTI), or any other IDs that are used to identify the anchor WTRU o Anchor WTRU location and/or its uncertainty range, o Anchor WTRU velocity and/or its uncertainty range,

I l l o Anchor WTRU coverage information (e.g., in coverage, out of coverage, cell ID), and/or o Anchor WTRU duplexing information (e.g., full duplex WTRU); and/or

• Anchor WTRU capability information: o (Maximum) transmit power, o Supported sensing methods (e.g., RTT), o Supported measurements (e.g., ToA, RSTD, AoA), o Supported maximum number of obstacles, o Available sensing start time and duration, and/or o Available WTRU energy.

[0614] Bistatic sensing request

[0615] In certain representative embodiments, a WTRU may receive a bistatic sensing request from one or more target WTRUs.

[0616] In one example, a WTRU may receive a bistatic sensing request from multiple target WTRU(s), such as through one of the sidelink specific signals (e.g., SCI, SL-MAC-CE, and/or PC5-RRC messages).

[0617] In one example, a request from a target WTRU may include an indication of the amount resources that may be transmitted per target WTRU. For example, the WTRU may receive (e.g., at least) any of the following:

• Bistatic RTT thresholds (e.g., threshold_min and thresholdjnax);

• SL-PRS transmission bandwidth (e.g., in terms of RBs, Hz); • Target WTRU’s total allocated energy for sensing (e.g., in terms of joules); and/or

[0618] In certain representative embodiments, a WTRU may receive a bistatic RTT threshold from the network.

[0619] In one example, a WTRU may receive the bistatic RTT thresholds (e.g., thresholdjnax, threshold_min) from the network. For example, each threshold may be specific (e.g., unique) to each target WTRU.

[0620] In another example, a WTRU may receive the bistatic RTT thresholds (e.g., thresholdjnax, threshold_min) from multiple target WTRUs. For example, each threshold may be specific (e.g., unique) to each target WTRU.

[0621] In certain representative embodiments, a WTRU may autonomously determine the bistatic RTT threshold from the network.

[0622] In another example, a WTRU may implicitly determine the bistatic thresholds based on the assistance information. For example, the WTRU may determine a thresholdjnax (e.g., Y1 ms) based on (e.g., at least) any of the following conditions:

• The QoS accuracy requirement is below a (pre)configured threshold,

• The QoS reliability requirement is below a (pre)configured threshold,

• The obstacle velocity is below a (pre)configured threshold,

• The uncertainty in the WTRU location is below a (pre)configured threshold,

• The distance between the WTRU and the target WTRU is above a (pre)configured threshold.

[0623] For example, the WTRU may determine another thresholdjnax (e.g., Y2 ms) otherwise.

[0624] For example, a WTRU may determine a threshold_min (e.g., Z1 ms) if the configured bandwidth is below a (pre)configure threshold and another threshold (e.g., Z2 ms) otherwise.

[0625] In another example, a WTRU may also be configured with one or more sets of thresholdjnax and threshold_min bistatic thresholds (e.g., via tables and/or equations) dependent on various values of the above-mentioned parameters. The WTRU may then, based on the determined values of the one or more parameters, select a suitable threshold_min and thresholdjnax from the (pre)configured set.

[0626] Obstacle/Target WTRU selection

[0627] In certain representative embodiments, a WTRU may determine a priority of an obstacle. For example, in FIG. 22, obstacle 1 202a may be determined as high priority, and obstacle 2 202b may be determined as medium priority. [0628] In one example, the WTRU may determine the obstacle priority based on obstacle information and/or target WTRU information.

[0629] In one example, the WTRU may determine its priority to the obstacle based on (e.g., at least) any of the following conditions:

• UE location and/or the associated uncertainty range,

• UE velocity and/or the associated uncertainty range,

• Obstacle location and/or the associated uncertainty range, and/or

• Obstacle velocity and/or the associated uncertainty range.

[0630] In one example, the WTRU may determine the priority of each target WTRU(s) to the obstacle based on (e.g., at least) any of the following:

• Target WTRU location and/or the associated uncertainty range,

• Target WTRU velocity and/or the associated uncertainty range,

• Obstacle location and/or the associated uncertainty range, and/or

• Obstacle velocity and/or the associated uncertainty range.

[0631] For example, in FIG. 22, target WTRU 102c may be determined as low priority, target WTRU 102b may be determined as high priority, and target WTRU 102a may be determined as high priority.

[0632] In another example, the WTRU may receive its priority and/or the priorities of one or more of the target WTRU(s) from the network based on the above-mentioned parameters.

[0633] In another example, the WTRU may receive the obstacle’s priorities of one or more of the target WTRU(s) from the corresponding target WTRU(s).

[0634] In certain representative embodiments, a WTRU may select the obstacle-target WTRU pair(s) for bistatic sensing.

[0635] In one example, the WTRU may determine to select the one or more obstacles and the associated target WTRUs as pair for bistatic sensing.

[0636] In one example, the WTRU may determine a subset of the obstacle-target WTRU pairs that may be suitable for bistatic sensing based on (e.g., at least) any of the following conditions:

• The WTRU determines that obstacle is within the range for bistatic sensing: o The expected bistatic RTT associated with the target WTRU is below the (pre)configured thresholdjnax, o The expected bistatic RTT associated with the target WTRU is above the (pre)configured threshold_min, and/or o The velocity of the WTRU is below a (pre)configured threshold;

• The WTRU’s obstacle priority is above a (pre)configured threshold: o The distance between the WTRU and the obstacle is below a (pre)configured threshold, o The velocity of the WTRU is above a (pre)configured threshold, o The relative velocity between the WTRU and the obstacle is above a (pre)configured threshold, o The uncertainty in WTRU location is above a (pre)configured threshold, and/or o The uncertainty in WTRU velocity is above a (pre)configured threshold;

• The target WTRU’s obstacle priority is above a (pre)configured threshold: o The distance between the target WTRU and the obstacle is below a (pre)configured threshold, o The velocity of the target WTRU is above a (pre)configured threshold, o The relative velocity between the target WTRU and the obstacle is above a (pre)configured threshold, o The uncertainty in target WTRU location is above a (pre)configured threshold, and/or o The uncertainty in target WTRU velocity is above a (pre)configured threshold,

• The target WTRU’s indicated sensing duration is below a (pre)configured threshold; and/or

• The overlap between the target WTRU’s indicated sensing window and the WTRU’s sensing window is above a (pre)configured threshold.

[0637] In one example, the WTRU may be configured with the conditions, thresholds and/or weights for each condition mentioned above by the network.

[0638] For example, as illustrated in FIG. 22, the WTRU may determine the priority for Obstacle 1 202a and Obstacle 2 202b from its perspective and/or from the perspective of the target WTRUs. For example, the priorities may be determined from the perspective of each WTRUs. Subsequently, the WTRU may select the target WTRUs according to the thresholds as listed above.

[0639] In certain representative embodiments, a WTRU may determine the total number of (e.g., unique) obstacles for bistatic sensing.

[0640] In one example, since the WTRU may select multiple target WTRU-obstacle pairs associated with different target WTRUs but a same obstacle, the WTRU may determine the total number of separate (e.g., unique) obstacles selected.

[0641] In one example, the WTRU may determine if two requests correspond to a same obstacle based on (e.g., at least) any of the following conditions:

• The distance between the two obstacle is below a (pre)configured threshold, o In one example, the threshold may also be dependent on the uncertainty of the obstacle location. For example, the WTRU may determine a large threshold if the uncertainty in obstacle location indicated by at least one of the requesting target WTRUs is above a (pre)configured threshold; • The difference between the velocities of the obstacle is below a (pre)configured threshold; and/or

• The difference in the expected AoA for bistatic sensing with respect to the two obstacles is below a (pre)configured threshold.

[0642] In certain representative embodiments, a WTRU may select the target WTRU(s) per obstacle for bistatic sensing per obstacle.

[0643] In one example, a WTRU may determine a maximum number of target WTRUs to support for bistatic sensing per obstacle. The WTRU may determine this based on (e.g., at least) any of the following conditions:

• The WTRU’s QoS requirements for sensing for each obstacle: o For example, the WTRU may associate the total number of target WTRUs per obstacle with WTRU’s QoS requirements, and/or o For example, the WTRU may associate one total number target WTRUs (e.g., 3) per obstacle if the QoS accuracy and/or reliability requirement is above a (pre)configured threshold and another total number of target WTRUs (e.g., 1) otherwise;

• The WTRU’s remaining sensing duration: o For example, the WTRU may associate the total number of target WTRUs per obstacle with WTRU’s remaining sensing duration, and/or o For example, the WTRU may associate one total number target WTRUs (e.g., 3) per obstacle if the remaining sensing duration is above a (pre)configured threshold and another total number of target WTRUs (e.g., 1) otherwise; and/or

• The WTRU’s remaining sensing energy: o For example, the WTRU may associate the total number of target WTRUs per obstacle with WTRU’s remaining sensing energy, and/or o For example, the WTRU may associate one total number target WTRUs (e.g., 3) per obstacle if the sensing energy is above a (pre)configured threshold and another total number of target WTRUs (e.g., 1) otherwise.

[0644] In another example, the WTRU may be (pre)configured by the network with the maximum number of target WTRUs that may be supported per obstacle.

[0645] In one example, the WTRU may determine to down select (e.g., reduce) the number of target WTRU(s) for bistatic sensing per obstacle if the total number is above the (pre)configured or the determined threshold. The WTRU may down select the target WTRUs based on (e.g., at least) any of the following:

• The target WTRU’s bistatic RTT thresholdjnax is above a (pre)configured threshold, o For example, as the bistatic thresholdjnax is associated with the target WTRU’s capabilities (e.g., transmission power), the WTRU may select the target WTRU with more capabilities; • The expected bistatic RTT is below a (pre)configured threshold, o For example, the WTRU may select the target WTRU such that the single bounce signal propagation distance from the target WTRU and the obstacle is below the threshold allowing higher sensing accuracy;

• The periodicity of the indicated measurement window is below a (pre)configured threshold, o For example, the measurement window periodicity may indicate the intended frequency of the SL-PRS resource transmission, and/or o The threshold may be associated with WTRU’s available energy and/or time/frequency resources for signal reception and measurement.

• The target WTRU’s velocity is below a (pre)configured threshold, o For example, if the velocity is above the threshold, the target WTRU may need to frequently (e.g., periodically, semi-persistently) transmit its location information for obstacle location;

• The target WTRU’s QoS requirements is below a (pre)configured threshold, o For example, QoS requirement (e.g., accuracy/reliability requirement) may be associated the available energy/capability for SL-PRS reception and/or measurement, and/or o For example, the required energy/capability for above threshold QoS requirement may exceed the energy/capability that may be allocated to each obstacle; and/or

• The target WTRU’s sensing duration is below a (pre)configured threshold, o For example, above threshold target WTRU’s sensing duration may exceed the sensing duration that may be allocated to each obstacle.

[0646] Resource allocation to the target WTRUs

[0647] In certain representative embodiments, a WTRU may allocate resources to each selected obstacle in the obstacle - WTRU pair for sensing.

[0648] In one example, a WTRU may associate different resources (e.g., time and/or frequency) for obstacle sensing for each obstacle from the total available set of resources.

[0649] In one example, the WTRU may associate X1 (e.g., seconds of) time resources and/or Y1 (e.g., Hz of) frequency resources based on (e.g., at least) any of the following conditions:

• The total number of selected obstacles is below a (pre)configured threshold,

• The (e.g., average) expected bistatic RTT associated with the target WTRU in the selected target WTRU-obstacle pair is above a (pre)configured threshold,

• The (e.g., average) bistatic RTT thresholdjnax associated with the target WTRU in the selected target WTRU-obstacle pair is below a (pre)configured threshold,

• The target WTRU’s indicated (e.g., average) measurement window duration is below a (pre)configured threshold, • The target WTRU’s indicated (e.g., average) measurement window periodicity is above a (pre)configured threshold,

• The target WTRU’s QoS requirements for sensing (e.g., accuracy/reliability) is below a (pre)configured threshold,

• The obstacle velocity is above a (pre)configured threshold,

• The uncertainty in obstacle location and/or velocity s above a (pre)configured threshold,

• The WTRU’s remaining sensing duration is above a (pre)configured threshold,

• The WTRU’s remaining sensing energy is above a (pre)configured threshold,

• Default configuration (e.g., the amount of resources for sensing is configured by the network or peer WTRU), and/or

• The WTRU’s indicated priority to the obstacle is above a (pre)configured threshold.

[0650] In another example, the WTRU may associate X2 (e.g., seconds of) time resources and/or Y2 (e.g., Hz of) frequency resources if the above conditions are not satisfied. In one example, X1 and/or Y1 may be smaller than X2 and/or Y2.

[0651] In another example, the WTRU may be configured with a mapping table by the network, associating resources with the parameters (e.g., duration of the window, RTT thresholds, QoS requirement) described herein. For example, the table may associate RTT threshold (e.g., 10 ms) with the time resources and/or frequency resources (e.g., bandwidth) for sensing (e.g., 10 ms, 100MHz).

[0652] In certain representative embodiments, a WTRU may allocate resources to each target WTRU for each selected obstacle in the obstacle - WTRU pair.

[0653] In one example, for each target WTRU in a selected obstacle - target WTRU pair, the WTRU may allocate the resources (e.g. time and/or frequency resources) from the total amount of resources allocated for the obstacle based on (e.g., at least) any of the following conditions:

• The time allocated to the obstacle associated with the target WTRU is above a (pre)configured threshold,

• The expected bistatic RTT is above a (pre)configured threshold,

• The bistatic RTT thresholdjnax associated with the target WTRU is below a (pre)configured threshold,

• The bistatic RTT threshold_min associated with the target WTRU is below a (pre)configured threshold,

• The target WTRU’s indicated measurement window duration is below a (pre)configured threshold,

• The target WTRU’s indicated measurement window periodicity is above a (pre)configured threshold,

• The target WTRU’s QoS requirements for sensing (e.g., accuracy/reliability) is below a (pre)configured threshold, • The target WTRU’s indicated priority to the obstacle is below a (pre)configured threshold,

• The target WTRU’s velocity is below a (pre)configured threshold,

• The target WTRU’s uncertainty in its location is below a (pre)configured threshold, and/or

• The target WTRU’s uncertainty in its velocity is below a (pre)configured threshold.

[0654] I n another example, the WTRU may associate another set of resources if the above conditions are not satisfied.

[0655] In certain representative embodiments, a WTRU may determine the measurement window for each obstacle for each selected obstacle in the obstacle - WTRU pair.

[0656] FIG. 23 is a time and frequency resource diagram illustrating proposed measurement window configurations 2302 and 2304 for different obstacles (e.g., Obstacle 1 202a and Obstacle 2 202b in FIG. 22). [0657] In one example, the WTRU may determine the measurement window (e.g., proposed measurement window) for each obstacle based on the indicated resources that it may propose to the selected target WTRUs.

[0658] In one example, the proposed measurement window may be determined per obstacle as the WTRU may measure the transmitted SL-PRS signals from (e.g., multiple) target WTRU(s) to determine its location. [0659] In one example, this determination, for each obstacle in the selected target WTRU-obstacle pair, may be based on (e.g., at least) any of the following:

• Start time: o For example, the WTRU may determine the start time based on the indicated start time of the proposed windows for the target WTRU associated with the obstacle (E.g., average, earliest, latest), o For example, the WTRU may determine the start time based on the QoS latency requirement of the selected target WTRU(s) associated with the obstacle:

■ For example, the WTRU may determine a start time T1 if the QoS latency requirement is above a (pre)configured threshold; the WTRU may determine a start time T2. In one example T 1 may be earlier than T2, o For example, the WTRU may determine the start time based its sensing window:

■ For example, the WTRU may determine the start time T1 if the start time of the sensing window is T2. For example, T1 may be later than T2, o For example, the WTRU may determine the start time based on the velocity of the target WTRU:

For example, the WTRU may determine the start time T1 if (e.g., average) velocity of the obstacle associated target WTRU(s) is above a (pre)configured threshold; the WTRU may determine start time T2 otherwise. For example, T 1 may be earlier than T2, o For example, the WTRU may determine the start time based on the velocity of the obstacle:

■ For example, the WTRU may determine a start time T1 is the velocity of the obstacle is above a (pre)configured threshold; the WTRU may determine start time T2 otherwise. For example, T1 may be earlier than T2, and/or o For example, the WTRU may determine the start time based on the velocity of the obstacle:

■ For example, the WTRU may determine a start time T1 is the velocity of the obstacle is above a (pre)configured threshold; the WTRU may determine start time T2 otherwise. For example, T1 may be earlier than T2;

• Measurement window duration: o For example, the WTRU may determine the measurement window duration based on the indicated duration in the windows indicated by the target WTRU associated with the obstacle:

■ For example, the WTRU may determine the measurement window duration based on the duration indicated by the associated target WTRU(s) (e.g., average, shortest, longest), o For example, the WTRU may determine the measurement window duration based on the amount to time and/or frequency resources allocated for each selected obstacle from the selected obstacle-target WTRU pair:

■ For example, the WTRU may associate a measurement window duration as D1 if the total time allocated to the obstacle is above a (pre)configured threshold; the WTRU may associate the window duration as D2 otherwise. In one example, D1 may be greater than D2, and/or

■ For example, the WTRU may associate a measurement window duration as D1 if the frequency resources allocated to the obstacle is below a (pre)configured threshold; the WTRU may associate the window duration as D2 otherwise. In one example, D1 may be smaller than D2, o For example, the WTRU may determine the measurement window duration based on the (e.g., average) bistatic RTT thresholdjnax for each obstacle in the selected obstacle-target WTRU pair:

■ For example, the WTRU may associate a measurement window duration as D1 if (e.g., average) thresholdjnax associated with the target WTRUs in the selected obstacle-target WTRU pair is above a (pre)configured threshold; the WTRU may associate the window duration as D2 otherwise,

■ In one example, D1 may be greater than D2, and/or

■ For example, an above threshold bistatic_RTT thresholdjnax may indicate a large bistatic sensing coverage area and hence may require more number of resources for obstacle sensing, o For example, the WTRU may determine the measurement window duration based on the QoS requirement for sensing:

■ For example, the WTRU may associate a measurement window duration as D1 if the target WTRU’s and/or the WTRU’s QoS accuracy and/or reliability requirement for sensing the obstacle is above a (pre)configured threshold; the WTRU may associate the window duration as D2 otherwise. In one example, D1 may be greater than D2, and/or

■ For example, the WTRU may associate a measurement window duration as D1 if the target WTRU’s and/or the WTRU’s QoS latency requirement for sensing the obstacle is above a (pre)configured threshold; the WTRU may associate the window duration as D2 otherwise. In one example, D1 may be smaller than D2. o For example, the WTRU may determine the measurement window duration based on the obstacle velocity:

■ For example, the WTRU may associate a measurement window duration as D1 if the obstacle velocity is above a (pre)configured threshold; the WTRU may associate the window duration as D2 otherwise. In one example, D1 may be smaller than D2, o For example, the WTRU may determine the measurement window duration based on the velocity of the WTRU and/or the target WTRU:

■ For example, the WTRU may associate a measurement window duration as D1 if the velocity of the WTRU and/or target WTRU is below a (pre)configured threshold; the WTRU may associate the window duration as D2 otherwise. In one example, D1 may be smaller than D2;

• Measurement window type (e.g., periodic, aperiodic, semi-persistent): o For example, the WTRU may determine the measurement window type based on the indicated window type by the target WTRU associated with the obstacle. o For example, the WTRU may determine a periodic measurement window type based on any of the following conditions:

■ the total available sensing duration is above a (pre)configured threshold, ■ the bandwidth for sensing is below a (pre)configured threshold,

■ the obstacle velocity is above a (pre)configured threshold,

■ the uncertainty in obstacle velocity is above a (pre)configured threshold,

■ the WTRU and/or the target WTRU velocity is above a (pre)configured threshold,

■ the uncertainty in the WTRU and/or the target WTRU velocity is above a (pre)configured threshold,

■ the QoS accuracy requirement is above a (pre)configured threshold, and/or

■ the QoS reliability requirement is above a (pre)configured threshold, o For example, the WTRU may determine an aperiodic measurement window type based on any of the following conditions:

■ the total available sensing duration is below a (pre)configured threshold,

■ the obstacle velocity is below a (pre)configured threshold,

■ the QoS accuracy requirement is below a (pre)configured threshold

■ the QoS latency requirement is above a (pre)configured threshold

■ the QoS reliability requirement is below a (pre)configured threshold

■ the obstacle velocity is below a (pre)configured threshold,

■ the uncertainty in obstacle velocity is below a (pre)configured threshold, o For example, the WTRU may determine a semi persistent measurement window type based on any of the following conditions:

■ the total available sensing duration is below a (pre)configured threshold,

■ the bandwidth for sensing is below a (pre)configured threshold,

■ the obstacle velocity is above a (pre)configured threshold,

■ the uncertainty in obstacle velocity is above a (pre)configured threshold,

■ the QoS accuracy requirement is below a (pre)configured threshold, and/or

■ the QoS reliability requirement is below a (pre)configured threshold; and/or

• Periodicity of the measurement window (if measurement type is semi-persistent or periodic): o For example, the WTRU may determine the measurement window duration based on the indicated periodicity in the windows indicated by the target WTRU associated with the obstacle (e.g., average, smallest, largest), o For example, the WTRU may determine the measurement window periodicity based on the amount to time and/or frequency resources allocated for each obstacle in the selected obstacle-target WTRU pair:

■ For example, the WTRU may associate a measurement window periodicity as P1 if the total time allocated to the obstacle is above a (pre)configured threshold; the WTRU may associate the window duration as P2 otherwise. In one example, P1 may be greater than P2, and/or

■ For example, the WTRU may associate a measurement window periodicity as P1 if the total frequency allocated to the obstacle is below a (pre)configured threshold; the WTRU may associate the window duration as P2 otherwise. In one example, P1 may be greater than P2, o For example, the WTRU may determine the measurement window periodicity based on the (e.g., average) bistatic RTT thresholdjnax for each obstacle in the selected obstacle-target WTRU pair:

■ For example, the WTRU may associate a measurement window periodicity as P1 if (e.g., average) thresholdjnax associated with the target WTRUs in the selected obstacle-target WTRU pair is above a (pre)configured threshold; the WTRU may associate the window periodicity as P2 otherwise, and/or

■ In one example, P1 may be greater than P2, o For example, the WTRU may determine the measurement window duration based on the obstacle velocity:

■ For example, the WTRU may associate a measurement window periodicity as P1 if the obstacle velocity is above a (pre)configured threshold; the WTRU may associate the window duration as P2 otherwise. In one example, P1 may be smaller than P2, o For example, the WTRU may determine the start time based on the velocity of the WTRU and/or target WTRU:

■ For example, the WTRU may associate a measurement window periodicity as P1 if the velocity of the WTRU and/or target WTRU is below a (pre)configured threshold; the WTRU may associate the window duration as P2 otherwise. In one example, P1 may be smaller than P2.

[0660] Bistatic Sensing Response

[0661] In certain representative embodiments, a WTRU may indicate the measurement window to the target WTRUs in the selected obstacle-target WTRU pair. [0662] In one example, a WTRU may agree to the bistatic sensing request (e.g., proposal) from the target WTRU and transmit the indication to the target WTRU (e.g., “Yes”, ACK) (e.g., via unicast), such as via one of the sidelink specific signals (e.g., SCI, SL-MAC CE, PC5 RRC).

[0663] In one example, the WTRU may transmit the proposed measurement window configurations to the target WTRUs. The WTRU may transmit any of the following measurement window information to a target WTRU:

• Duration of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds)

• Measurement window type (e.g., periodic, aperiodic, semi-persistent), and/or

• Periodicity of the window (e.g., in terms of number of symbols, slots, frames, subframes, seconds). [0664] For each target WTRU, the WTRU may (e.g., also) transmit any of the following assistance information for SL-PRS configuration:

• Other target WTRU(s) (e.g., target WTRU associated with the selected obstacle) information: o Target WTRU IDs, o Target WTRU locations and/or the associated uncertainty range, o Target velocity locations and/or the associated uncertainty range, o Amount of time (e.g., in terms of number of symbols, slots, frames, subframes, seconds) and/or frequency resources allocated (e.g., in Hz, number of REs/RBs) per target WTRU,

• Total WTRU’s allocated sensing duration, and/or

• Total sensing bandwidth.

[0665] In another example, the WTRU may send a negative response (e.g., “No”, NACK) to the bistatic sensing proposal to (i) any target WTRUs in the obstacle-target WTRU pair that were not selected for bistatic sensing, and/or (ii) any target WTRUs in the obstacle-target WTRU pair that was selected but the target WTRU was not selected for bistatic sensing.

[0666] In certain representative embodiments, a WTRU may receive an acknowledgement of the response from the target WTRUs.

[0667] In one example, the WTRU may receive a message from at least one or more target WTRUs associated with the selected target WTRU-obstacle pair.

[0668] In one example, the WTRU may receive a positive acknowledgement (e.g., “Yes”, ACK) indicating that the target WTRU has accepted the proposed measurement window.

[0669] The WTRU may additionally receive a message with the assistance information for SL-PRS configurations including any of the configured SL-PRS resource ID(s), SL-PRS resource set ID(s), and/or time, frequency, periodicity and/or spatial configurations. [0670] In one example, the WTRU may receive a negative acknowledgement (e.g., “No”, NACK) indicating that the target WTRU has rejected the proposed measurement window.

[0671] In certain representative embodiments, a WTRU may activate the measurement window and receive the SL-PRS resources from the target WTRUs.

[0672] In one example, the WTRU may activate the proposed measurement window for an obstacle if the number of target WTRUs from the selected obstacle-target WTRU pair for each obstacle that sent a positive acknowledgement is above a (pre)configured threshold.

[0673] In one example, the WTRU may receive the receives the SL-PRS in the SL-PRS resources from the target WTRUs during the activated measurement window.

[0674] FIG. 24 is a signaling diagram illustrating signaling exchanges between a network, a WTRU and target WTRUs. The procedure shown in FIG. 24 may be used for bistatic obstacle prioritization for multiple bistatic sensing requests as described above. At 2402, a (e.g., anchor) WTRU 904 may receive one or more RS (e.g., SL-PRS) configurations from a network (e.g., gNB 180 or LMF). At 2404, the WTRU 904 may receive multiple discovery messages from the target WTRU 102a, the target WTRU 102b, and the target WTRU 102c. At 2406, the WTRU 904 may send a discovery response message to the target WTRU 102a, the target WTRU 102b, and the target WTRU 102c. At 2408, the WTRU 904 may receive multiple bistatic sensing requests from the target WTRU 102a, the target WTRU 102b, and the target WTRU 102c. For example, the WTRU 904 may send a bistatic request response at 2410 which accepts the bistatic sensing requests to the target WTRU 102a and the target WTRU 102b. The bistatic request response may include proposed measurement window configurations. At 2412, the WTRU 904 may send a bistatic request response to the target WTRU 102c which declines the bistatic sensing request from the target WTRU 102c. At 2412, the WTRU 904 may receive a response from the target WTRU 102a and the target WTRU 102b which accept the proposed measurement window configurations. At 2414, the WTRU 904 may receive one or more SL-PRSs which are transmitted from the target WTRU 102a and the target WTRU 102b. For example, the target WTRU 102a may transmit SL-PRSs during a respective proposed measurement window configuration, and the target WTRU 102b may transmit SL-PRSs during another respective proposed measurement window configuration.

[0675] FIG. 25 is a flow diagram illustrating an example procedure for anchor device selection. At 2502, a WTRU may receive information indicating at least one positioning reference signal (RS) configuration. At 2504, the WTRU may determine (e.g., bistatic) threshold information associated with sensing (e.g., minimum and maximum thresholds for bistatic sensing). At 2506, the WTRU may detect an obstacle (e.g., using monostatic sensing). At 2508, the WTRU may determine a second (e.g., anchor) WTRU in the vicinity of the WTRU for bistatic sensing based on the threshold information, such as based on a (e.g., bistatic) round trip time. At 2510, the WTRU may send one or more RSs using first time/frequency resources associated with the positioning RS configuration. At 2512, the WTRU may receive from, the other (e.g., anchor) WTRU, information indicating a (e.g., bistatically sensed) location of the obstacle.

[0676] In some representative embodiments, the procedure of FIG. 25 may be modified to include other features discussed above in the present disclosure.

[0677] FIG. 26 is a flow diagram illustrating an example procedure for group-based sensing. At 2602, a first WTRU may receive, from a second WTRU, a sensing request. The sensing request may include information indicating a location of an obstacle and a location of the second WTRU. At 2604, the first WTRU may determine one or more anchor WTRUs. At 2606, the first WTRU may determine a group from the one or more anchor WTRUs based on (i) respective locations of the one or more anchor WTRUs and (ii) the location of the second WTRU. At 2608, the first WTRU may send, to the one or more anchor WTRUs of the group, information indicating at least one positioning RS configuration. At 2610, the first WTRU may determine a sub-group from the group-based on (i) respective locations of the one or more anchor WTRUs of the group and (ii) the location of the obstacle. At 2612, the first WTRU may activate the sub-group for bistatic sensing. At 2614, the first WTRU may receive, from at least one anchor WTRU in the sub-group, information indicating a location of the obstacle.

[0678] In some representative embodiments, the procedure of FIG. 26 may be modified to include other features discussed above in the present disclosure.

[0679] FIG. 27 is a flow diagram illustrating an example procedure for sensing mode selection. At 2702, a WTRU may receive positioning RS configuration information. At 2704, the WTRU may determine first threshold information associated with bistatic sensing and second threshold information associated with monostatic sensing. At 2706, the WTRU may receive, from a second WTRU, information indicating (i) a location of the second WTRU, (ii) a location of the obstacle, and (iii) a target sensing zone. At 2708, the WTRU may perform, with the second WTRU, bistatic sensing using the positioning RS configuration information based on (i) a first round trip time (RTT) associated with a location of the first WTRU, the location of the obstacle, and the location of the second WTRU, (ii) a second RTT between associated with the location of the first WTRU and the location of the obstacle, (iii) the first threshold information, and (iv) the second threshold information.

[0680] In some representative embodiments, the procedure of FIG. 27 may be modified to include other features discussed above in the present disclosure.

[0681] FIG. 28 is a flow diagram illustrating an example procedure for prioritization of bistatic sensing. At 2802, a WTRU may receive information indicating at least one positioning RS configuration. At 2804, the WTRU may determine threshold information associated with (e.g., bistatic) sensing. At 2806, the WTRU may determine one or more second WTRUs. At 2808, the WTRU may determine first priority information associated with the obstacle based on a location of the first WTRU and a location of the object. At 2810, the WTRU may determine second priority information associated with the obstacle based on respective locations of the one or more second WTRUs and the location of the object. At 2812, the WTRU may determine one or more obstacle-second WTRU pairs based on (i) round trip time (RTT) information associated with the one or more second WTRUs and the threshold information, (ii) the first priority information, and/or (iii) the second priority information. At 2814, the WTRU may send information indicating proposed measurement window information to the one or more obstacle-second WTRU pairs. At 2816, the WTRU may perform bistatic sensing with the one or more second WTRUs of the determined one or more obstacle-second WTRU pairs using the at least one positioning RS configuration and the proposed measurement window.

[0682] In some representative embodiments, the procedure of FIG. 28 may be modified to include other features discussed above in the present disclosure.

[0683] FIG. 29 is a flow diagram illustrating an example procedure for bistatic sensing using TRPs. For example, the procedure in FIG. 29 may be implemented by a WTRU. At 2902, the WTRU may receive information indicating (i) a plurality of SRSp configurations, (ii) a first time threshold and a second time threshold which are associated with the plurality of SRSp configurations, and (iii) assistance information indicating a plurality of TRP locations of a plurality of TRPs. At 2904, the WTRU may detect an (e.g., coarse) obstacle location of an obstacle. At 2906, the WTRU may select a first set of the TRPs from the plurality of TRPs. For example, the first set of TRPs may be WTRU-preferred TRPs for bistatic sensing. For example, each TRP of the first set may be associated with a RTT, between the obstacle location and the TRP location of the respective TRP, which is above the first time threshold and below the second time threshold (e.g., a RTT that satisfies a sensing coverage area). At 2908, the WTRU may send, to a network, an uplink bistatic sensing request which includes information indicating any of (i) the first set, (ii) the obstacle location, and/or (iii) a WTRU location of the WTRU. At 2910, the WTRU may receive, from the network, an uplink bistatic sensing acknowledgment which includes information indicating a second set of the TRPs. For example, the second set of TRPs may be selected by the network, such as based on the first set of TRPs indicated by the WTRU. At 2912, the WTRU may select one or more SRSp configurations from the plurality of SRSp configurations based on the first time threshold, the second time threshold, and the TRP locations of the second set of the TRPs. At 2914, the WTRU may transmit one or more SRSps using one or more SRSp resources of the selected one or more SRSp configurations. For example, the second set of TRPs may receive the transmitted SRSps and perform bistatic sensing of the obstacle.

[0684] For example, the RTT between the obstacle location and the TRP location of the respective TRP may be (e.g., determined as) a bistatic RTT.

[0685] For example, the WTRU may estimate the RTT between the obstacle location and the TRP location of the respective TRP. [0686] For example, the selecting of the one or more SRSp configuration from the plurality of SRSp configurations at 2912 may be based on the first time threshold, the second time threshold, and a sensing coverage area associated with the TRP locations of the second set of the TRPs.

[0687] For example, the WTRU may select the one or more SRSp resources as a subset of resources included in the selected one or more SRSp configurations.

[0688] For example, an AoD associated with (e.g., each of) the one or more SRSp resources may be within a sensing coverage area associated with the TRP locations of the second set of the TRPs.

[0689] For example, the WTRU may send, to the network, information indicating the one or more SRSps resources (and/or configurations) prior to the transmitting of the one or more SRSps.

[0690] For example, the detecting of the obstacle location of the obstacle at 2904 may be performed using monostatic sensing of the obstacle (e.g., coarse location).

[0691] For example, the first set of the TRPs may be the same as the second set of TRPs.

[0692] For example, at least one TRP is different between the first set of the TRPs and the second set of the TRPs. As an example, the network may select the second set of the TRPs from the first set of the TRPs which are selected by the WTRU.

[0693] For example, the WTRU may receive location information associated with the obstacle based on the transmitted one or more SRSps which are received by the the second set of TRPs.

[0694] In some representative embodiments, the procedure of FIG. 29 may be modified to include other features discussed above in the present disclosure.

[0695] FIG. 30 is a flow diagram illustrating an example procedure for bistatic sensing using TRPs. For example, the procedure in FIG. 30 may be performed by a network entity (e.g., a TRP, a gNB, or other entity in the RAN 113). At 3002, the network entity may send, to a WTRU, information indicating (i) a plurality of SRSp configurations, (ii) a first time threshold and a second time threshold which are associated with the plurality of SRSp configurations, and (iii) assistance information indicating a plurality of TRP locations of a plurality of TRPs. At 3004, the network entity may receive, from the WTRU, an uplink bistatic sensing request which includes information indicating any of (i) a first WTRU-preferred set of the TRPs from the plurality of TRPs, (ii) a first (e.g., coarse) obstacle location of an obstacle, and/or (iii) a WTRU location of the WTRU. For example, each TRP of the first set may be associated with a RTT, between the obstacle location and the TRP location of the respective TRP, which is above the first time threshold and below the second time threshold. At 3006, the network entity may send, to the WTRU, an uplink bistatic sensing acknowledgment which includes information indicating a second network-selected set of the TRPs. For example, the second set of TRPs may be selected by the network, such as based on the first set of TRPs indicated by the WTRU. At 3008, the network entity may send, to the WTRU, information indicating a second (e.g., fine) obstacle location of the obstacle. For example, the second obstacle location may be (e.g., determined) based on reception of one or more SRSps using one or more SRSp resources of one or more of the plurality of SRSp configurations by the second network-selected set of the TRPs.

[0696] For example, the network entity may select, from the plurality of TRPs, the second set of the TRPs based on the first WTRU-preferred set of the TRPs.

[0697] For example, the network entity may determine the second obstacle location based on reception of one or more SRSps using one or more SRSp resources of the one or more SRSp configurations by the second network-selected set of the TRPs.

[0698] For example, the network entity may receive, from the second network-selected set of the TRPs, location information based on reception of one or more SRSps using one or more SRSp resources of the one or more SRSp configurations by the second network-selected set of the TRPs. The network entity may determine the second (e.g., fine) obstacle location based on the received location information.

[0699] In some representative embodiments, the procedure of FIG. 30 may be modified to include other features discussed above in the present disclosure.

[0700] FIG. 31 is a flow diagram illustrating an example procedure for bistatic sensing using TRPs. For example, the procedure in FIG. 31 may be implemented by a WTRU. At 3102, the WTRU may receive information indicating a set of reference signal (RS) configurations (e.g., PRS, SRSp, CSI-RS, DM-RS, SSB, and/or etc.). At 3104, the WTRU may send an uplink bistatic sensing request which includes information indicating a first set of (e.g., preferred) TRPs, an obstacle location of an obstacle, and a WTRU location of the WTRU. At 3106, the WTRU may receive an uplink bistatic sensing acknowledgment which includes information indicating a second set of (e.g., network-selected) TRPs. At 3108, the WTRU may select one or more of the RS configurations from the set of RS configurations based on locations of the second set of TRPs. At 3110, the WTRU may transmit one or more RSs using one or more resources of the selected one or more RS configurations.

[0701] In some representative embodiments, the procedure of FIG. 31 may be modified to include other features discussed above in the present disclosure.

[0702] FIG. 32 is a flow diagram illustrating an example procedure for bistatic sensing using TRPs. For example, the procedure in FIG. 32 may be implemented by a network entity. At 3202, the network entity may send (e.g., to a WTRU) information indicating a set of RS configurations (e.g., associated with bistatic sensing). At 3204, the network entity may receive an uplink bistatic sensing request which includes information indicating a first set of TRPs determined by a WTRU, an obstacle location of an obstacle, and a WTRU location of the WTRU. At 3206, the network entity may send an uplink bistatic sensing acknowledgment which includes information indicating a second set of TRPs. At 3208, the network entity may send location information associated with the obstacle based on reception of one or more RSs transmitted by the WTRU using one or more resources of one or more RS configurations of the set of RS configurations. For example, the network entity and/or the second set of TRPs may determine the location information (e.g., fine location of the obstacle) based on the RSs transmitted by the WTRU.

[0703] In some representative embodiments, the procedure of FIG. 32 may be modified to include other features discussed above in the present disclosure.

[0704] FIG. 33 is a flow diagram illustrating an example procedure for group-based sensing. For example, the procedure in FIG. 33 may be implemented by a first WTRU. At 3302, the first WTRU may receive a sensing request which includes information indicating a first (e.g., coarse) obstacle location of an obstacle and a location of another (e.g., second) WTRU. For example, the sensing request may be received from the other WTRU. At 3304, the first WTRU may determine a set of anchor WTRUs based on locations of the anchor WTRUs, the first obstacle location , and the location of the other (e.g., second) WTRU. At 3306, the first WTRU may activate the set (e.g., a subset) of anchor WTRUs to perform bistatic sensing using at least one reference signal (RS) configuration. At 3308, the first WTRU may receive, from at least one anchor WTRU of the set of anchor WTRUs, information indicating a second (e.g., fine) obstacle location of the obstacle based on the bistatic sensing using the at least one RS configuration.

[0705] In some representative embodiments, the procedure of FIG. 33 may be modified to include other features discussed above in the present disclosure.

[0706] FIG. 34 is a flow diagram illustrating an example procedure for group-based sensing. For example, the procedure in FIG. 33 may be implemented by an anchor WTRU. At 3402, the anchor WTRU may receive, from another WTRU, information indicating to activate a set of anchor WTRUs for bistatic sensing using at least one RS configuration. At 3404, the anchor WTRU may perform bistatic sensing using the at least one RS configuration. At 3406, the anchor WTRU may send, to the other WTRU or to another anchor WTRU of the set, information indicating an (e.g., fine) obstacle location of an obstacle based on the bistatic sensing. [0707] In some representative embodiments, the procedure of FIG. 33 may be modified to include other features discussed above in the present disclosure.

[0708] FIG. 35 is a flow diagram illustrating an example procedure for sensing mode selection. For example, the procedure in FIG. 35 may be implemented by a first WTRU. At 3502, the first WTRU may receive information indicating a RS configuration. At 3504, the first WTRU may determine first threshold information (e.g., for a bistatic sensing coverage area) associated with bistatic sensing and second threshold information (e.g., for a monostatic sensing range) associated with monostatic sensing. At 3506, the first WTRU may receive, from another (e.g., second) WTRU, information indicating any of (i) a location of the other (e.g., second) WTRU, (ii) a location of an obstacle, and (iii) a target sensing zone. At 3508, the first WTRU may performing monostatic sensing or bistatic sensing (e.g., with the second WTRU) with respect to the target sensing zone according to the positioning RS configuration based on (i) a first round trip time (RTT) associated with a location of the first WTRU, the location of the obstacle, and the location of the second WTRU, (ii) a second RTT between associated with the location of the first WTRU and the location of the obstacle, (iii) the first threshold information, and (iv) the second threshold information.

[0709] In some representative embodiments, the procedure of FIG. 35 may be modified to include other features discussed above in the present disclosure.

[0710] FIG. 36 is a flow diagram illustrating an example procedure for prioritization of bistatic sensing. For example, the procedure in FIG. 36 may be implemented by a first WTRU. At 3602, the first WTRU may receive information indicating at least one RS configuration. At 3604, the first WTRU may determine a set of second WTRUs. At 3606, the first WTRU may determine one or more obstacle-second WTRU pairs based on (i) round trip time (RTT) information associated with the set of second WTRUs and threshold information, and (ii) priority information associated with the obstacle and/or the set of second WTRUs. At 3608, the first WTRU may send information indicating a measurement window associated with bistatic sensing to the one or more obstacle-second WTRU pairs. At 3610, the first WTRU may perform, during the measurement window, bistatic sensing with the one or more second WTRUs of the determined one or more obstacle- second WTRU pairs using the at least one positioning RS configuration.

[0711] In some representative embodiments, the procedure of FIG. 36 may be modified to include other features discussed above in the present disclosure.

[0712] In certain representative embodiments, a WTRU may receive information indicating at least one RS (e.g., PRS, SRSp, CSI-RS, DM-RS, SSB, etc.) configuration. The WTRU may determine threshold information associated with sensing. The WTRU may detect an obstacle. The WTRU may determine an anchor WTRU in the vicinity of the WTRU for bistatic sensing based on the threshold information. The WTRU may send one or more RSs using first time/frequency resources associated with the positioning RS configuration. The WTRU may receive, from the anchor WTRU, information indicating a location of the obstacle.

[0713] For example, the WTRU may detect the obstacle by sending towards the obstacle, and receiving from the obstacle, one or more RSs using second time/frequency resources associated with the positioning RS configuration.

[0714] For example, the WTRU may determine the anchor WTRU in the vicinity of the WTRU for bistatic sensing by performing discovery of the anchor WTRU.

[0715] For example, the WTRU may determine the anchor WTRU in the vicinity of the WTRU for bistatic sensing by selection of the anchor WTRU for bistatic sensing based on any of (i) a RTT associated with the WTRU, the obstacle, and the anchor WTRU, (ii) a minimum threshold associated with the threshold information, and/or (iii) a maximum threshold associated with the threshold information.

[0716] For example, the WTRU may determine the first time/frequency resources associated with the positioning RS configuration based on a minimum threshold and/or a maximum threshold. [0717] For example, the WTRU may, before sending the one or more RSs using the first time/frequency resources, send to the anchor WTRU information indicating the first time/frequency resources.

[0718] In certain representative embodiments, a first WTRU may receive, from a second WTRU, a sensing request. For example, the sensing request may include information indicating a location of an obstacle and a location of the second WTRU. The first WTRU may determine one or more anchor WTRUs. The first WTRU may determine a group from the one or more anchor WTRUs based on (i) respective locations of the one or more anchor WTRUs and (ii) the location of the second WTRU. The first WTRU maysend, to the one or more anchor WTRUs of the group, information indicating at least one RS configuration. The first WTRU may determine a sub-group from the group-based on (i) respective locations of the one or more anchor WTRUs of the group and (ii) the location of the obstacle. The first WTRU may activate the sub-group for bistatic sensing. The first WTRU may receive, from at least one anchor WTRU in the sub-group, information indicating a location of the obstacle.

[0719] For example, the first WTRU may determine the one or more anchor WTRUs by performing discovery of (e.g., the respective locations of) the one or more anchor WTRUs.

[0720] For example, the first WTRU may determine the group from the one or more anchor WTRUs based on respective distances between the one or more anchor WTRUs and the second WTRU being below a threshold.

[0721] For example, the first WTRU may determine the sub-group from the group based on respective distances between the one or more anchor WTRUs of the group and the obstacle being below a threshold.

[0722] For example, the first WTRU may activate the sub-group for bistatic sensing by sending, to the subgroup, information indicating the respective locations of the one or more anchor WTRUs of the sub-group and/or respective bistatic sensing roles of the one or more anchor WTRUs of the sub-group.

[0723] For example, the first WTRU may modify the sub-group, and/or deactivate the sub-group-based on the respective locations of the one or more anchor WTRUs.

[0724] In certain representative embodiments, a first WTRU may receive RS (e.g., PRS, SRSp, CSI-RS, DM-RS, SSB, etc.) configuration information. The first WTRU may determine first threshold information associated with bistatic sensing and second threshold information associated with monostatic sensing. The first WTRU may receive, from a second WTRU, information indicating (i) a location of the second WTRU, (ii) a location of the obstacle, and (iii) a target sensing zone. The first WTRU may perform, with the second WTRU, bistatic sensing using the RS configuration information based on (i) a first round trip time (RTT) associated with a location of the first WTRU, the location of the obstacle, and the location of the second WTRU, (ii) a second RTT associated with the location of the first WTRU and the location of the obstacle, (iii) the first threshold information, and (iv) the second threshold information. [0725] For example, the first WTRU may determine that the first RTT satisfies the first threshold information. The first WTRU may determine that the second RTT satisfies the second threshold information. [0726] For example, the first threshold information may include a first threshold and a second threshold. The first WTRU may determine that the first RTT satisfies the first threshold information by determining that the first RTT is above the first threshold, and determining that the first RTT is below the second threshold.

[0727] For example, the second threshold information may include a third threshold. The first WTRU may determine that the second RTT satisfies the second threshold information by determining that the second RTT is above the third threshold.

[0728] For example, the first WTRU may send, to the second WTRU, information indicating the location of the first WTRU based on a distance between the location of the first WTRU and the location of the obstacle being below a threshold.

[0729] In certain representative embodiments, a first WTRU may receive RS (e.g., PRS, SRSp, CSI-RS, DM-RS, SSB, etc.) configuration information. The first WTRU may determine first threshold information associated with bistatic sensing and second threshold information associated with monostatic sensing. The first WTRU may receive, from a second WTRU, information indicating (i) a location of the second WTRU, (ii) a location of the obstacle, and (iii) a target sensing zone. The first WTRU may perform monostatic sensing using the positioning RS configuration based on (i) a RTT associated with a location of the first WTRU and the location of the obstacle, (ii) the second threshold information.

[0730] In certain representative embodiments, a first WTRU may receive RS (e.g., PRS, SRSp, CSI-RS, DM-RS, SSB, etc.) configuration information. The first WTRU may determine threshold information associated with sensing. The first WTRU may determine one or more second WTRUs. The first WTRU may determine first priority information associated with the obstacle based on a location of the first WTRU and a location of the object. The first WTRU may determine second priority information associated with the obstacle based on respective locations of the one or more second WTRUs and the location of the object. The first WTRU may determine one or more obstacle-second WTRU pairs based on (i) round trip time (RTT) information associated with the one or more second WTRUs and the threshold information, (ii) the first priority information, and/or (iii) the second priority information. The first WTRU may send information indicating proposed measurement window information to the one or more obstacle-second WTRU pairs. The first WTRU may perform bistatic sensing with the one or more second WTRUs of the determined one or more obstacle-second WTRU pairs using the at least one positioning RS configuration and the proposed measurement window.

[0731] For example, a respective second WTRU may be determined for a respective obstacle-second WTRU pair based on (i) a RTT between the location of the first WTRU, the location of the object, and the location of the respective second WTRU satisfying the threshold information, (ii) the first priority information being above a first threshold, and/or (iii) the second priority information being above a second threshold.

[0732] For example, the first priority information may be based on one or more parameters associated with the first WTRU and/or the obstacle.

[0733] For example, the second priority information, for each respective second WTRU, may be based on one or more parameters associated with the respective second WTRU and/or the obstacle.

[0734] For example, the first WTRU may receive information indicating a request for bistatic sensing from the one or more second WTRUs. The request may include measurement window information. The proposed measurement window information may be based on the measurement window information included in the request from the respective second WTRUs of the respective obstacle-second WTRU pairs.

[0735] For example, the first WTRU may determine the one or more second WTRUs by performing discovery of the one or more second WTRUs.

[0736] References

[0737] Each of the contents of the following references is incorporated by reference herein:

[1] 3GPP Technical Report, TR 22.837, ““Study on Integrated Sensing and Communication”, V1.0.0, 2023-03;

[2] 3GPP TSG-SA WG1 Meeting #98e, S1-221115, “Sensing Mode”, 2023-05; and

[3] 3GPP Technical Specification, TS 38.321 , “ NR; Medium Access Control (MAC)”, v17.2.0, 2022-10.

[0738] Conclusion

[0739] Although features and elements are provided above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations may be made without departing from its spirit and scope, as will be apparent to those skilled in the art. No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly provided as such. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods or systems.

[0740] The foregoing embodiments are discussed, for simplicity, with regard to the terminology and structure of wireless communication capable devices, (e.g., radio wave emitters and receivers). However, the embodiments discussed are not limited to these systems but may be applied to other systems that use other forms of electromagnetic waves or non-electromagnetic waves such as acoustic waves.

[0741] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used herein, the term "video" or the term "imagery" may mean (e.g., at least) any of a snapshot, single image and/or multiple images displayed over a time basis. As another example, when referred to herein, the terms "user equipment" and its abbreviation "UE", the term "remote" and/or the terms "head mounted display" or its abbreviation "HMD" may mean or include (i) a wireless transmit and/or receive unit (WTRU); (ii) (e.g., at least) any of a number of embodiments of a WTRU; (iii) a wireless-capable and/or wired-capable (e.g., tetherable) device configured with, inter alia, some or all structures and functionality of a WTRU; (iii) a wireless-capable and/or wired-capable device configured with less than all structures and functionality of a WTRU; or (iv) the like. Details of an example WTRU, which may be representative of any WTRU recited herein, are provided herein with respect to FIGs. 1 A-1 D. As another example, various disclosed embodiments herein supra and infra are described as utilizing a head mounted display. Those skilled in the art will recognize that a device other than the head mounted display may be utilized and some or all of the disclosure and various disclosed embodiments can be modified accordingly without undue experimentation. Examples of such other device may include a drone or other device configured to stream information for providing the adapted reality experience.

[0742] In addition, the methods provided herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, WTRU, terminal, base station, RNC, or any host computer.

[0743] Variations of the method, apparatus and system provided above are possible without departing from the scope of the invention. In view of the wide variety of embodiments that can be applied, it should be understood that the illustrated embodiments are examples only, and should not be taken as limiting the scope of the following claims. For instance, the embodiments provided herein include handheld devices, which may include or be utilized with any appropriate voltage source, such as a battery and the like, providing any appropriate voltage.

[0744] Moreover, in the embodiments provided above, processing platforms, computing systems, controllers, and other devices that include processors are noted. These devices may include at least one Central Processing Unit ("CPU") and memory. In accordance with the practices of persons skilled in the art of computer programming, reference to acts and symbolic representations of operations or instructions may be performed by the various CPUs and memories. Such acts and operations or instructions may be referred to as being "executed," "computer executed" or "CPU executed."

[0745] One of ordinary skill in the art will appreciate that the acts and symbolically represented operations or instructions include the manipulation of electrical signals by the CPU. An electrical system represents data bits that can cause a resulting transformation or reduction of the electrical signals and the maintenance of data bits at memory locations in a memory system to thereby reconfigure or otherwise alter the CPU's operation, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties corresponding to or representative of the data bits. It should be understood that the embodiments are not limited to the above- mentioned platforms or CPUs and that other platforms and CPUs may support the provided methods.

[0746] The data bits may also be maintained on a computer readable medium including magnetic disks, optical disks, and any other volatile (e.g., Random Access Memory (RAM)) or non-volatile (e.g., Read-Only Memory (ROM)) mass storage system readable by the CPU. The computer readable medium may include cooperating or interconnected computer readable medium, which exist exclusively on the processing system or are distributed among multiple interconnected processing systems that may be local or remote to the processing system. It should be understood that the embodiments are not limited to the above-mentioned memories and that other platforms and memories may support the provided methods.

[0747] In an illustrative embodiment, (e.g., at least) any of the operations, processes described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer- readable instructions may be executed by a processor of a mobile unit, a network element, and/or any other computing device.

[0748] There is little distinction left between hardware and software implementations of aspects of systems. The use of hardware or software is generally (but not always, in that in certain contexts the choice between hardware and software may become significant) a design choice representing cost versus efficiency tradeoffs. There may be various vehicles by which processes and/or systems and/or other technologies described herein may be effected (e.g., hardware, software, and/or firmware), and the preferred vehicle may vary with the context in which the processes and/or systems and/or other technologies are deployed. For example, if an implementer determines that speed and accuracy are paramount, the implementer may opt for a mainly hardware and/or firmware vehicle. If flexibility is paramount, the implementer may opt for a mainly software implementation. Alternatively, the implementer may opt for some combination of hardware, software, and/or firmware. [0749] The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples include one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples may be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In an embodiment, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), and/or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, may be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and or firmware would be well within the skill of one of skill in the art in light of this disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein may be distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a CD, a DVD, a digital tape, a computer memory, and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communications link, a wireless communication link). [0750] Those skilled in the art will recognize that it is common within the art to describe devices and/or processes in the fashion set forth herein, and thereafter use engineering practices to integrate such described devices and/or processes into data processing systems. That is, at least a portion of the devices and/or processes described herein may be integrated into a data processing system via a reasonable amount of experimentation. Those having skill in the art will recognize that a typical data processing system may generally include one or more of a system unit housing, a video display device, a memory such as volatile and non-volatile memory, processors such as microprocessors and digital signal processors, computational entities such as operating systems, drivers, graphical user interfaces, and applications programs, one or more interaction devices, such as a touch pad or screen, and/or control systems including feedback loops and control motors (e.g., feedback for sensing position and/or velocity, control motors for moving and/or adjusting components and/or quantities). A typical data processing system may be implemented utilizing any suitable commercially available components, such as those typically found in data computing/communication and/or network computing/communication systems. [0751] The herein described subject matter sometimes illustrates different components included within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality may be achieved. Hence, any two components herein combined to achieve a particular functionality may be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated may also be viewed as being "operably connected", or "operably coupled", to each other to achieve the desired functionality, and any two components capable of being so associated may also be viewed as being "operably couplable" to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.

[0752] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various si ng ular/pl ural permutations may be expressly set forth herein for sake of clarity.

[0753] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," ). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, where only one item is intended, the term "single" or similar language may be used. As an aid to understanding, the following appended claims and/or the descriptions herein may include usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim including such introduced claim recitation to embodiments including only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should be interpreted to mean "at least one" or "one or more"). The same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C" is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together). In those instances where a convention analogous to "at least one of A, B, or C" is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B." Further, the terms "(e.g., at least) any of' followed by a listing of a plurality of items and/or a plurality of categories of items, as used herein, are intended to include "(e.g., at least) any of," "any combination of," "any multiple of," and/or "any combination of multiples of" the items and/or the categories of items, individually or in conjunction with other items and/or other categories of items. Moreover, as used herein, the term "set" is intended to include any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero. And the term "multiple", as used herein, is intended to be synonymous with "a plurality".

[0754] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0755] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths As a non-limiting example, each range discussed herein may be readily broken down into a lower third, middle third and upper third As will also be understood by one skilled in the art all language such as "up to," "at least," "greater than," "less than," and the like includes the number recited and refers to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1 , 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1 , 2, 3, 4, or 5 cells, and so forth. [0756] Moreover, the claims should not be read as limited to the provided order or elements unless statedo that effect. In addition, use of the terms "means for" in any claim is intended to invoke 35 U.S.C. §112, If 6 or means-plus-function claim format, and any claim without the terms "means for" is not so intended.

Claims

CLAIMS What is claimed is:

1. A method implemented by a wireless transmit/receive unit (WTRU), the method comprising: receiving information indicating (i) a plurality of sounding reference signal for positioning (SRSp) configurations, (ii) a first time threshold and a second time threshold which are associated with the plurality of SRSp configurations, and (iii) assistance information indicating a plurality of transmission/reception point (TRP) locations of a plurality of TRPs; detecting an obstacle location of an obstacle; selecting a first set of the TRPs from the plurality of TRPs, wherein each TRP of the first set is associated with a round trip time (RTT), between the obstacle location and the TRP location of the respective TRP, which is above the first time threshold and below the second time threshold; sending, to a network, an uplink bistatic sensing request which includes information indicating (i) the first set, (ii) the obstacle location, and (iii) a WTRU location of the WTRU; receiving, from the network, an uplink bistatic sensing acknowledgment which includes information indicating a second set of the TRPs; selecting one or more SRSp configurations from the plurality of SRSp configurations based on the first time threshold, the second time threshold, and the TRP locations of the second set of the TRPs; and transmitting one or more SRSps using one or more SRSp resources of the selected one or more SRSp configurations.

2. The method of claim 1, wherein the RTT between the obstacle location and the TRP location of the respective TRP is a bistatic RTT.

3. The method of any one of claims 1-2, further comprising: estimating the RTT between the obstacle location and the TRP location of the respective TRP.

4. The method of any one of claims 1-3, wherein the selecting of the one or more SRSp configuration from the plurality of SRSp configurations is based on the first time threshold, the second time threshold, and a sensing coverage area associated with the TRP locations of the second set of the TRPs.

5. The method of any one of claims 1-4, further comprising: selecting the one or more SRSp resources as a subset of resources included in the selected one or more SRSp configurations.

6. The method of any one of claims 1-5, wherein an angle of departure (AoD) associated with the one or more SRSp resources is within a sensing coverage area associated with the TRP locations of the second set of the TRPs.

7. The method of any one of claims 1 -6, further comprising: sending, to the network, information indicating the one or more SRSps resources prior to the transmitting of the one or more SRSps.

8. The method of any one of claims 1-7, wherein the detecting of the obstacle location of the obstacle uses monostatic sensing of the obstacle location.

9. The method of any one of claims 1-8, wherein the first set of the TRPs is the same as the second set of TRPs.

10. The method of any one of claims 1 -9, wherein at least one TRP is different between the first set of the TRPs and the second set of the TRPs.

11 . The method of any one of claims 1 -10, further comprising: receiving location information associated with the obstacle based on the transmitted one or more SRSps which are received by the the second set of TRPs.

12. A wireless transmit/receive unit (WTRU) comprising: a processor, memory, and a transceiver which are configured to: receive information indicating (i) a plurality of sounding reference signal for positioning (SRSp) configurations, (ii) a first time threshold and a second time threshold which are associated with the plurality of SRSp configurations, and (iii) assistance information indicating a plurality of transmission/reception point (TRP) locations of a plurality of TRPs, detect an obstacle location of an obstacle, select a first set of the TRPs from the plurality of TRPs, wherein each TRP of the first set is associated with a round trip time (RTT), between the obstacle location and the TRP location of the respective TRP, which is above the first time threshold and below the second time threshold, send, to a network, an uplink bistatic sensing request which includes information indicating (i) the first set, (ii) the obstacle location, and (iii) a WTRU location of the WTRU, receive, from the network, an uplink bistatic sensing acknowledgment which includes information indicating a second set of the TRPs, select one or more SRSp configurations from the plurality of SRSp configurations based on the first time threshold, the second time threshold, and the TRP locations of the second set of the TRPs, and transmit one or more SRSps using one or more SRSp resources of the selected one or more SRSp configurations.

13. The WTRU of claim 12, wherein the RTT between the obstacle location and the TRP location of the respective TRP is a bistatic RTT.

14. The WTRU of any one of claims 12-13, wherein the processor, memory, and the transceiver are configured to: estimate the RTT between the obstacle location and the TRP location of the respective TRP.

15. The WTRU of any one of claims 12-14, wherein the selecting of the one or more SRSp configuration from the plurality of SRSp configurations is based on the first time threshold, the second time threshold, and a sensing coverage area associated with the TRP locations of the second set of the TRPs.

16. The WTRU of any one of claims 12-15, wherein the processor, memory, and the transceiver are configured to: select the one or more SRSp resources as a subset of resources included in the selected one or more SRSp configurations.

17. The WTRU of any one of claims 12-16, wherein an angle of departure (AoD) associated with the one or more SRSp resources is within a sensing coverage area associated with the TRP locations of the second set of the TRPs.

18. The WTRU of any one of claims 12-17, wherein the processor, memory, and the transceiver are configured to: send, to the network, information indicating the one or more SRSps resources prior to the transmitting of the one or more SRSps.

19. The WTRU of any one of claims 12-18, wherein the processor, memory, and the transceiver are configured to detect the obstacle location of the obstacle using monostatic sensing of the obstacle location.

20. The WTRU of any one of claims 12-19, wherein the first set of the TRPs is the same as the second set of TRPs.

21 . The WTRU of any one of claims 12-20, wherein at least one TRP is different between the first set of the TRPs and the second set of the TRPs.

22. The WTRU of any one of claims 12-21 , wherein the processor, memory, and the transceiver are configured to receive location information associated with the obstacle based on the transmitted one or more SRSps which are received by the second set of TRPs.

23. A network entity comprising: a processor, memory, and a transceiver which are configured to: send, to a wireless transmit/receive unit (WTRU), information indicating (i) a plurality of sounding reference signal for positioning (SRSp) configurations, (ii) a first time threshold and a second time threshold which are associated with the plurality of SRSp configurations, and (iii) assistance information indicating a plurality of transmission/reception point (TRP) locations of a plurality of TRPs, receive, from the WTRU, an uplink bistatic sensing request which includes information indicating (i) a first WTRU-preferred set of the TRPs from the plurality of TRPs, (ii) a first obstacle location of an obstacle, and (iii) a WTRU location of the WTRU, wherein each TRP of the first set is associated with a round trip time (RTT), between the obstacle location and the TRP location of the respective TRP, which is above the first time threshold and below the second time threshold, send, to the WTRU, an uplink bistatic sensing acknowledgment which includes information indicating a second network-selected set of the TRPs, and send, to the WTRU, information indicating a second obstacle location of the obstacle, wherein the second obstacle location is based on reception of one or more SRSps using one or more SRSp resources of one or more of the plurality of SRSp configurations by the second network-selected set of the TRPs.

24. The network entity of claim 23, wherein the processor, memory, and the transceiver are configured to select, from the plurality of TRPs, the second set of the TRPs based on the first WTRU-preferred set of the TRPs.

25. The network entity of any one of claims 23-24, wherein the processor, memory, and the transceiver are configured to determine the second obstacle location based on reception of one or more SRSps using one or more SRSp resources of the one or more SRSp configurations by the second network-selected set of the TRPs.

26. The network entity of any one of claims 23-24, wherein the processor, memory, and the transceiver are configured to: receive, from the second network-selected set of the TRPs, location information based on reception of one or more SRSps using one or more SRSp resources of the one or more SRSp configurations by the second network-selected set of the TRPs, and determine the second obstacle location based on the received location information.